UNIVERSITY OF
ILLINOIS LIBRARY
AT URBANA-CHAMPAIGN
BIOUOGY
2001
FB
Botany
RIES. NO 3
William Burger, Editor
Family #113 Euphorbiaceae
William Burger Michael Huft
October 31, 1995 Publication 1469
3ARYO
996
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PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY
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FIELDIANA
Botany
NEW SERIES, NO. 36
FLORA COSTARICENSIS
William Burger, Editor
Family #113 Euphorbiaceae
William Burger
Curator, Department of Botany Field Museum of Natural History Roosevelt Road at Lake Shore Drive Chicago, Illinois 60605-2496
Michael Huft
Research Associate
Department of Botany
Field Museum of Natural History
Roosevelt Road at Lake Shore Drive
Chicago, Illinois 60605-2496
Accepted May 11, 1995 Published October 31, 1995 Publication 1469
PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY
© 1995 Field Museum of Natural History
ISSN 00 15-0746 PRINTED IN THE UNITED STATES OF AMERICA
Table of Contents
INTRODUCTION v
ACKNOWLEDGMENTS v
EUPHORBIACEAE 1
Key 1 : Key to the Genera of Euphorbi-
aceae in Costa Rica 2
Key 2: Artificial Key to Genera and Un- usual Species 7
Illustrations of Euphorbiaceae 14
Descriptions of Genera and Species 46
Acalypha 46
Croton 84
Euphorbia 113
Phyllanthus 140
LITERATURE CITED 163
LIST OF ACCEPTED SPECIES 1 64
INDEX . 166
List of Illustrations
1 . Shrubs or treelets with deeply lobed leaves: species of Manihot and Ricinus 14
2. Vines and subshrubs with lobed leaves: species of Croton, Cnidoscolus, and Tragia 15
3. Trees and shrubs with deeply to slight- ly lobed leaves with palmate venation: species of Jatropha 16
4. Slender-stemmed vines with lobed or compound leaves: species of Dale- champia 17
5. Slender-stemmed vines: species of Dal- echampia, Plukenetia, and Tragia 18
6. Plants with very small leaves: species
of Chamaesyce and Euphorbia 19
7. Plants with small opposite leaves: spe- cies of Chamaesyce 20
8. Plants with small alternate leaves: spe- cies of Phyllanthus 21
9. Plants with small alternate leaves: spe- cies of Phyllanthus 22
10. Herbaceous or weedy plants: species of Caperonia, Croton, and Dysopsis 23
1 1 . Herbaceous or weedy plants: species of Acalypha, Argythamnia, and Sebasti-
ania . . 24
12. Trees and shrubs with serrate elliptic leaves: species ofAcidoton, Alchornea, Bernardia, Cleidion, Croton, and Gym- nanthes 25
13. Plants with larger oblanceolate serrate leaves: species of Adenophaedra, Dale- champia, and Pausandra 26
1 4. Shrubs or herbs with serrate leaves and laciniate styles: species of Acalypha .... 27
15. Shrubs with serrate leaves and lacini- ate styles: species of Acalypha 28
16. Plants with slightly serrate leaves and stellate hairs: species of Croton 29
17. Trees and shrubs with flat peltate
hairs: species of Croton 30
18. Trees and shrubs with larger ovate leaves, stellate hairs, and glands at
apex of petiole: species of Croton 31
19. Trees and shrubs with larger ovate or oblong leaves and stellate or peltate
hairs: species of Croton 32
20. Trees with larger leaves: species of Aparisthmium, Conceveiba, Sagotia,
and Tetrorchidium 33
2 1 . Trees with glands on petioles or a thickened petiole apex: species of Gar- cia and Tetrorchidium 34
22. Trees with glands on petioles: species
of Sapium 35
23. Trees with glands on petioles (Sapium spp.) or shrubs with glands along lami- na margins (Stillingia sp.) 36
24. Trees with slightly serrate leaves and subpalmate or palmate venation: spe- cies of Alchornea and Alchorneopsis .... 37
25. Trees and shrubs with entire or subser- rate leaves: species of Actinostemon, Margaritaria, Phyllanthus, and Sebas- tiania 38
26. Trees and shrubs with entire elliptic leaves: species of Gymnanthes, Mabea,
and Pera 39
27. Trees and shrubs with entire elliptic leaves: species of Amanoa and Dry- petes 40
28. Trees with spicate inflorescences or in- florescence branches: species of Hy- eronima and Richeria 41
29. Herbs or weak-stemmed shrubs with entire leaves and white sap: species of Euphorbia 42
30. Shrubs and trees with small entire leaves and white sap: species of Eu- phorbia 43
in
3 1 . Climbers and unusual plants: species 32. Trees and shrubs with distinctive
ofAdelia, Mabea, Omphalea, and Plu- leaves: species of Astrocasia, Cod-
kenetia 44 iaeum, Hippomane, and Hura . . 45
IV
Introduction
This is the ninth issue in the Flora Costaricensis series. The first dealt with the Piperaceae, family number 41 (Fieldiana, Bot. 35, 1971). The second included families numbered 42 through 53, Chlo- ranthaceae through Urticaceae (Fieldiana, Bot. 40, 1 977). The third issue covered the Gramineae (Po- aceae) and was authored by Richard Pohl (Field- iana, Bot., n.s. No. 4, 1980). The fourth issue in- cluded families numbered 54 through 70, Podo- stemaceae through Caryophyllaceae (Fieldiana, Bot., n.s. No. 13, 1983). The fifth issue covered families 200 and 201, the Acanthaceae, authored by L. H. Durkee, and Plantaginaceae (Fieldiana, Bot., n.s. No. 18, 1986). The sixth issue included families 80 and 8 1 , Lauraceae and Hernandiaceae
(Fieldiana, Bot., n.s. No. 23, 1990). The seventh issue included families numbered 97 through 103, Krameriaceae through Zygophyllaceae (Fieldiana, Bot., n.s. No. 28, 1991). The eighth issue included family 202, the Rubiaceae (Fieldiana, Bot., n.s. No. 33, 1993).
In the figures, leaves and leafy stems are drawn to the same scale throughout. Enlarged flowers and fruits are drawn to the same scale on an individual plate unless otherwise noted. The closed scales represent centimeters, and the open scales repre- sent millimeters. The figures are somewhat dia- grammatic and represent the senior author's con- cept of a common or characteristic morphology.
Acknowledgments
We wish to thank the staff of the Museo Na- tional de Costa Rica for their assistance in col- lecting programs over many years. The National Science Foundation and the National Geographic Society helped support many of these collecting activities. The Missouri Botanical Garden and the Institute Nacional de Biodiversidad have been es- pecially active in enriching our knowledge of Costa Rica's flora in recent years. Dr. Michael Huft, on the staff of the Missouri Botanical Garden and stationed at the Field Museum, worked with Neo- tropical euphorbs for more than a decade. His determinations and taxonomic concepts served as
the foundation for the present treatment. The col- lections of the Field Museum, the Missouri Bo- tanical Garden, Duke University, and the U.S. National Herbarium were consulted in preparing this treatment, and we thank those institutions for the use of their materials.
We have benefited from the annotations and publications of many taxonomists; they are ac- knowledged in the generic treatments and in the keys to genera. Three anonymous reviewers were very helpful, providing many detailed corrections and useful suggestions.
FLORA COSTARICENSIS Family #113 Euphorbiaceae
EUPHORBIACEAE
By William Burger and Michael Huft
Trees and shrubs or less often herbs, vines, and lianas, sometimes with thick green cactus-like stems and re- duced leaves in African and ornamental species, monoe- cious (bisexual) or dioecious (unisexual), sap often with colored or whitish latex (sap strongly caustic in Hippom- ane and some Euphorbia spp.), glabrous or pubescent, trichomes simple, stellate, scurfy, or rounded and peltate with flat apex (cf. Crotori), stinging hairs present in some genera (cf. Cnidoscolus and Tragia); stipules usually 2 and lateral at the petiole base (rarely 1 or 0), often falling early (caducous). Leaves usually alternate (opposite in Chamaesyce, Euphorbia spp., et al.), simple (rarely tri- foliolate or palmately compound as in Dalechampia spp. and Heved), petioles usually present, often with promi- nent glands distally or at the base of the blade (Croton, Sapium, et al.); leaf blades entire to serrate, sometimes palmately lobed (rarely irregularly pinnately lobed as in Codiaeum, Euphorbia spp.), glabrous to pubescent, ve- nation pinnate or palmate, often with glands along the edge or imbedded in blade, domatia rarely present. In- florescences terminal, axillary or extra-axillary, usually solitary or few/node, unisexual or bisexual, the bisexual usually with the 2 flowers proximal and the more nu- merous $ flowers distal, very variable in form (spikes, racemes, cymes, thyrses, paniculate or of solitary or fas- ciculate flowers) but most often with flowers in distal cymes, inflorescences forming pseudo-flowers (pseudan- thia) in Chamaesyce, Euphorbia, and Pedilanthus (called cyathia) and with less tightly organized pseudanthia in Dalechampia and Pera; flowers always unisexual but the pseudanthia usually bisexual, sessile or pedicellate, usu- ally subtended by bracts, bracts sometimes with 2 lateral glands. Male flowers radially symmetrical, perianth whorls 1 or 2 (rarely 0), calyx with 3-6 sepals or calyx lobes, valvate or imbricate in bud, glabrous or puberu- lent, petals present or absent, a disk usually present (an- nular, lobed, flat or glandular); stamens (1-2) 3-many, usually as many or twice as many as the perianth parts, filaments free or united into a column (a parasol-like androecium in Astrocasia, mushroom-like in Omphalea, strobilus-like protuberances in Hura, distally branched and with many anthers in Ricinus), anthers 2- or 4-thecous, usually dehiscing longitudinally, pollen grains of many differing types and often important in deter- mining generic relationships; a pistillode present or ab- sent. Female flowers radially symmetrical, perianth of 1 or 2 whorls (reduced or absent in a number of genera), calyx with 3-8 sepals or calyx lobes, imbricate, valvate or united in bud, corolla usually of separate petals or absent, disk present or absent, annular to lobed or cu-
pulate, staminodes usually absent; ovary superior, loc- ules usually 3 (1-20), styles usually the same number as the locules, free or united into a short or long column, style branches simple or divided to laciniate distally, ovules 1 or 2 in each locule, usually pendulous. Fruits usually capsules (schizocarps), rarely berries or drupes, the capsules characteristically separating septicidally into 2-valved cocci (mericarps) that open loculicidally and explosively on the inner face, a central columella often remaining after dehiscence; seeds often with an adaxial line or scar (ventral raphe), a thickened or fleshy caruncle often present at the micropylar attachment site, surfaces smooth to rugose, endosperm usually copious and oily, sometimes containing poisonous compounds.
The Euphorbiaceae are a large and important family with an estimated 7,700 species (Mabber- ley, 1987) in 317 genera (Webster, 1994b). Except for the polar regions, the family is worldwide in range but with the great majority of species in tropical and subtropical regions. The family in- cludes important agricultural taxa (Hevea, Mani- hot, Ricinus), medicinal plants, timber trees, and garden ornamentals (Acalypha, Codiaeum, Eu- phorbia, Ricinus) (see Mabberley, 1987, and other references under Literature Cited). The taxonomy of the Euphorbiaceae was recently the subject of a symposium (in Ann. Missouri Bot. Card. 81, parts 1 and 2, 1994). The relationships of the Eu- phorbiaceae have been the subject of many dif- ferent opinions (Webster, 1987). For a recent over- view of the family, see Webster (1994a, b).
The Euphorbiaceae are often difficult to iden- tify, both as to family and as to genera. The small unisexual flowers of great morphological diversity (often on unisexual trees and shrubs) account for some of this difficulty. Flowering material may be difficult to recognize as euphorbiaceous when only $ flowers are present. The usually three-parted ovaries, capsular fruits often breaking open explo- sively, and the characteristic seeds allow many fruiting collections to be quickly determined to family. The presence of milky or colored latex/sap or stellate-lepidote-peltate hairs can aid in deter- mination of some genera. Many species of Eu- phorbiaceae have flat or elevated glands at or near the junction of the petiole and leaf blade or small glands along the edge of the blade. Specimens of
FIELDIANA: BOTANY, N.S., NO. 36, OCTOBER 31, 1995, PP. 1-169
Euphorbiaceae may be mistaken for species of Fla- courtiaceae (but these usually have bisexual flow- ers), Moraceae (especially Sorocea and Trophis), and Urticaceae. Ornamental leafless succulent spe- cies with spines are often confused with Cactaceae, but the flowers and fruits easily distinguish the two families. Also, succulent euphorbs never have the tiny hooked hairs (glochids) found in many cacti, whereas cacti rarely have the milky sap found in many succulent euphorbs.
To aid in identification, we provide two separate keys to genera. The first is a technical key based on the characteristics that help define the genera,
and this key may be useful over a broader region. This key is based on the key developed by Webster (in Webster & Huft, 1988) and to a lesser extent on one by Gillespie (1993). The second key is an artificial key that is intended to be easy to use but that may not be helpful with atypical material or material new to southern Central America. Hope- fully, the illustrations will serve as an additional aid to identification, especially when critical floral features are not available. The illustrations are ar- ranged in a series of artificial "look-alike" group- ings.
Key 1: Key to the Genera of Euphorbiaceae in Costa Rica (Based on the Key of Webster in Webster & Huft, 1988.)
.,
la.
Ovules 2 in each locule of the ovary (seeds 1/locule in Drypetes and in Astrocasid); seeds 1-2 in each locule of the fruit, often 6/fruit (also 1-4/fruit), without caruncle; whitish latex absent; leaf blades never lobed, usually entire to obscurely serrate, usually lacking imbedded laminar glands, usually pinnately veined; trichomes simple or peltate [subfamily Phyllanthoideae and Croizatia of
the Oldfieldioideae] 2
Ib. Ovule 1 in each locule of the ovary; seeds usually 3/fruit, seeds with or without an apical caruncle; whitish or colored latex present or absent; leaf blades often serrate or lobed (also entire), often
with glands on blade or petiole, venation pinnate or palmate; trichomes various 10
2a. Petals present in the flowers 3
2b. Petals absent in the flowers 5
3a. Petals equaling or longer than the sepals; filaments connate and forming a parasol-like androecium; 9 disk forming a thin corolla-like cup; seeds with copious endosperm [rare
in southern Central America] Astrocasia
3b. Petals much shorter than the sepals; filaments free or connate, not forming a parasol- like androecium; 9 flower without a thin cupulate disk; seeds with little or copious
endosperm 4
4a. Plants monoecious (bisexual); stipules united above the petiole (intrapetiolar); petals glabrous; styles bifid and expanded; columella narrowed toward apex, without apical
wings Amanoa
4b. Plants dioecious (unisexual); stipules not united above the petiole; petals puberulent;
style twice bifid (pistil with 1 2 style branches); columella expanded distally forming 3
papery wings [eastern Panama and South America, not included in text] . . Croizatia
5a. $ inflorescences spikes or racemes; 3 flowers with prominent pistillode; plants dioecious
(unisexual) 6
5b. $ inflorescences of axillary flower clusters or on deciduous branchlets if racemose; $ flowers
lacking a prominent pistillode; plants monoecious (bisexual) or dioecious 7
6a. Trichomes simple; calyx deeply lobed (almost of separate sepals); <5 inflorescences spicate with sessile flower clusters; anther thecae not pendulous; ovary 2-3-locular;
fruits dry capsules Richeria
6b. Trichomes mostly peltate; calyx with short lobes; $ inflorescences with alternate branch- es; anther thecae pendulous; ovary 2-locular; fruits fleshy and drupaceous
Hyeronima
7a. $ flowers with a central intrastaminal disk; ovary with 1 or 2 locules, stigmas sessile and expanded; fruits drupaceous; ovules 1/locule; dioecious (unisexual) trees Drypetes
FIELDIANA: BOTANY
7b. $ flowers without a central disk or the disk outside the stamens if present; ovary with 3-6 locules and styles, styles present and bifid, stigmas slender or expanded; fruits mostly capsules;
ovules 2/locule; plants monoecious (bisexual) or dioecious 8
8a. Ovary with 4 or 5 locules (rarely 3, 6), styles 4 or 5 (3, 6); fruits irregularly dehiscent; seeds with fleshy outer coat and hard bony inner coat; $ flower with annular (ring-like) disk and 4 free stamens; distal branchlets persisting, not resembling pinnate leaves; dioecious trees
Margaritaria
8b. Ovary with 3 (rarely 2) locules, styles 3 (2); fruit usually breaking into valves; seeds without both a fleshy and bony layer; 3 flowers with 2 or 3 stamens, or without a disk when 4 stamens are present; distal branchlets often deciduous and resembling pinnate leaves; monoecious or
dioecious 9
9a. Common wild trees, shrubs, and herbs with green leaves; seeds dry, ventral faces not in-
vaginated; floral disk usually present Phyllanthus
9b. Ornamental garden shrubs with variegated leaves; seeds with fleshy exotesta, ventral face
invaginated; floral disk absent Breynia
lOa. (from Ib) Floral bracts without glands at the base (present in Tetrorchidium); sepals imbricate to valvate, usually covering the anthers completely in bud, rarely petaloid; petals present or absent;
disk often present; trichomes various; leaves simple to palmately lobed or compound 11
1 Ob. Floral bracts with 2 glands at the base (but sometimes difficult to see, absent in Hura and Senfelderd); sepals imbricate or not well developed; anthers mostly exposed in bud; petals absent and the sepals not petaloid, but glands of involucral cup may have petal-like lobes; disk absent or minute; trichomes simple or absent (dendritic in Mabed); leaves without lobes [subfamily Euphorbioideae]
37
11 a. Petals absent, or if petals present the leaf blades with pinnate venation; petioles lacking stalked glands (but glands imbedded in leaf blades often present); seeds lacking caruncles (caruncles present in Pera and Ricinus); trichomes simple or attached at the center (peltate in Pera); flowers in axillary clusters, racemes, or spikes (these sometimes aggregated into
panicles); latex usually absent, rarely white (subfamily Acalyphoideae) 12
lib. Petals present, at least in the $ flowers, or else calyx petaloid (except in Tetrorchidium, with raised foliar glands, and in Croton punctatus); leaves often palmately veined or lobed; petioles or bases of the leaf blades often with stalked or prominent glands; seeds with caruncles or fleshy (except in Garcia); trichomes simple, attached in the center, stellate or peltate; inflo- rescences various; latex clear, colored or whitish (subfamily Crotonoideae) 29
12a. Petals present in both $ and 2 flowers [flowers in racemes; 6 flowers with 10 stamens;
seeds usually foveolate] 13
1 2b. Petals absent (3 petals in 2 Caryodendrori) 14
1 3a. Leaves serrulate, 2° veins straight, more than 6/side and clearly parallel; trichomes
simple or gland-tipped; 6 flowers with a pistillode Caperonia
1 3b. Leaves entire, 2° veins arcuate-ascending, fewer than 5/side and not clearly par- allel; trichomes often attached at the center; 3 flowers lacking a pistillode
Argythamnia
1 4a. Flowers sessile within a globose stipitate flower-like inflorescence, at first enclosed by the petal-like involucre; inflorescences resembling globose flower buds borne on leafless nodes below the leaves; seeds smooth and shiny black with caruncle [dioecious trees
with peltate or stellate trichomes] Pera
14b. Flowers not sessile nor enclosed in a stipitate involucre; inflorescences not resembling
pedicellate flower buds in early stages; seeds neither black nor shiny 15
1 5a. Flowers in a complex flower-like arrangement (pseudanthium) with 2 usually conspic- uous palmately veined bracts often held in a vertical plane [ovary and fruit usually armed with stinging hairs; plants mostly vines or lianas with palmately veined or lobed
leaves, or with palmately compound leaves] Dalechampia
1 5b. Flowers not in a complex pseudanthium with 2 large palmately veined bracts held in
a vertical plane 16
1 6a. Stamens resembling little trees, with many distal branches bearing 80-many anthers;
BURGER & HUFT: FLORA COSTARICENSIS
leaf blades peltate and palmately lobed; inflorescences with 2 flowers distal and 6 flowers
proximal; seeds with caruncles [introduced plants] Ricinus
1 6b. Stamens not branched and tree-like with so many anthers; leaf blades never peltate or palmately lobed; inflorescences usually with 9 flowers proximal; seeds with minute
caruncle or caruncle absent 17
1 7a. <5 flowers with 4 sepals imbricate in 2 whorls, stamens 2, completely united and mush- room-shaped with connective enlarged and fleshy; latex reddish or purplish; fruits 8-
1 2 cm diam. [globose; plants usually lianas] Omphalea
1 7b. <5 flowers with 3-5 valvate sepals, stamens 3-many (if 2 then the connective not en- larged); latex not reddish or purplish; fruits less than 7 cm diam 18
1 8a. Stinging hairs present [styles undivided and connate basally; disk absent; seeds smooth,
caruncle absent] 19
1 8b. Stinging hairs absent 20
1 9a. Anthers lacking a minute tuft of apical hairs; bisexual vines; leaf blades usually
cordate at base, usually with many stinging hairs Tragia
1 9b. Anthers with a minute apical tuft of stinging hairs (often difficult to see); unisexual
shrubs and trees; leaf blades cuneate at base, glabrescent Acidoton
20a. Styles basally connate into a long column; inflorescences bisexual and axillary; ovary
4-locular, strongly keeled; lianas [leaf blades with 2 circular glands at base]
Plukenetia
20b. Styles free or basally connate; inflorescences unisexual, various; ovary 2-3-locular, not
strongly keeled; trees, shrubs, or herbs 21
2 la. Styles usually divided into many slender laciniate branches; anthers minute (ca. 0.1 mm wide) with narrow pendulous- vermiform thecae (but difficult to see); 2 bracts much larger than the <5 or if not the ovary verrucose [<3 inflorescences usually slender congested
spikes] Acalypha
2 1 b. Styles various, but only divided into slender laciniate branches in Adelia; anthers usually more than 0.2 mm wide and the thecae not narrow and pendulous- vermiform; 2 bracts
not conspicuously larger or differently shaped than the 6 bracts 22
22a. Ovary with 2 locules and 2 elongate free entire styles [stamens usually 8, pistillode absent; seeds tuberculate, lacking a caruncle, dry; trichomes often minutely stellate]
Alchornea
22b. Ovary with 3 locules and with 3 bifid styles (or the seeds fleshy if styles are simple)
23
23a. Stamens fewer than 10; plants unisexual (dioecious) 24
23b. Stamens more than 10; plants unisexual or bisexual (monoecious) 27
24a. Herbs with creeping stems; stipules thin and persisting; capsule thin-walled . . .
Dysopsis
24b. Trees and shrubs with erect stems; stipules absent or caducous; capsules thick- walled 25
25a. Leaves usually tripliveined; stipules absent; seed coat fleshy; a pubescent pistillode
present in <5 flowers [inflorescences axillary; 2 flowers subsessile] Alchorneopsis
25b. Leaves pinna tely veined; stipules present; seed coat not fleshy; pistillode absent
in 2 flowers 26
26a. Leaves without glands; stamens 3 , disk absent in <3 flowers; styles broadly expanded
and stigma-like; seeds < 1 cm long Adenophaedra
26b. Leaf blades with flat laminar glands at the adaxial base; stamens 4-7, disk large
in $ flowers; styles short; seeds > 1 cm long Caryodendron
27a. Stamens more than 50 in $ flowers, anther connective enlarged; stipules thickened [disk
absent in 2 flowers] Cleidion
27b. Stamens less than 30 in each 6 flower, anther connective not enlarged; stipules thin
28
28a. Styles much divided and laciniate distally, 2 flowers with long (> 18 mm) pedicels; fruits long-pendulous; leaf blades without glands Adelia
FIELDIANA: BOTANY
28b. Styles once or twice bifid (6 or 1 2 style branches), not laciniate, 2 flowers sessile or on pedicels to 6 mm long; fruits not pendulous; leaf blades with conspicuous glands near the base Bernardia
29a. (from 1 1 b) Rowers without petals; stamens 3/flower, anthers peltate and appearing 4-thecous; seeds fleshy, lacking a caruncle [dioecious/unisexual trees and shrubs; leaves with stalked petiolar glands and trichomes attached at the center] Tetrorchidium
29b. Flowers with petals present, or if petals absent then the calyx petaloid or trichomes peltate; stamens 8 or more per flower, anthers not appearing 4-thecous; seeds not fleshy, with a caruncle (except Garcia) 30
30a. Flowers without petals, but the calyx petal-like [leaves palmately lobed; trichomes simple; sap white; plants monoecious/bisexual; inflorescences terminal and dichasial or paniculate; stamens 8-10] 31
30b. Flowers with petals, or if petals absent then the trichomes peltate; sap not whitish .... 32 3 la. Stinging hairs absent; calyx yellow to greenish or purple and often resembling a rotate
corolla; <5 flowers with free filaments and central interstaminal disk Manihot
31b. Stinging hairs present (sometimes very few); calyx whitish and not resembling a rotate corolla; $ flowers with connate filaments and extrastaminal disk Cnidosculus
32a. Anthers inflexed in bud; some peltate or stellate trichomes usually present [<5 flowers with 8-many stamens, filaments free; inflorescences spicate or racemose (never branched); plants usually monoecious/bisexual in Central America; seeds with caruncles] Croton
32b. Anthers usually erect in bud; trichomes not stellate or peltate 33
33a. Calyx opening into valvate segments; $ flowers with 6-13 petals, stamens 30-100 or more; seeds without caruncles [trichomes simple; bisexual trees or shrubs] Garcia
33b. Calyx of initially separate imbricate sepals; <3 flowers with usually 5 petals, stamens 12 or fewer; seeds with caruncles 34
34a. Leaves palmately veined or lobed; stamens mostly 8-12, filaments partly united; inflores- cences terminal and dichasial, usually bisexual; trichomes simple or with gland-tipped seg- ments Jatropha
34b. Leaves pinnately veined; stamens 3—40, filaments free; inflorescences terminal or axillary, usually unisexual (unisexual or bisexual in Sagotia), spicate to racemose or paniculate; tri- chomes never with gland-tipped segments 35
35a. Stamens 3-7; 2 flower with petals connate into a tube longer than the calyx; unisexual trees [inflorescences axillary and spiciform; trichomes simple and attached at the center but often difficult to see] Pausandra
35b. Stamens 15—40; 2 flower lacking petals or the petals shorter than the calyx; bisexual shrubs and trees 36
36a. $ flowers without a disk; styles deeply bifid; inflorescences usually terminal, 1-12 cm long; leaves never lobed or with bright variegated colors; native trees Sagotia
36b. $ flowers with a lobed disk; styles simple and unlobed inflorescences usually axillary, 10-20 cm long; leaves often with lateral lobes and brilliant variegated colors; introduced garden
shrubs Codiaeum
37a. (from lOb) Flowers not pseudanthial (as in 37b), without a well-developed involucral cup; flowers
in spicate, racemose, or paniculate inflorescences; styles simple; stamens in whorls or united, not
in radiating groups of 5 within a calyx cup or calyx tube; shrubs or trees, rarely herbs 38
37b. Flowers pseudanthial, actually flower-like inflorescences (called cyathia) in which the involucral
bracts are united to form a calyx-like cup, usually with 1-5 glands along the edge of the involucral
cup and these often with petal-like structures, central pistil actually a naked 9 flower on an articulated
stipe (pedicel), styles bifid or simple; stamens usually in 5 lateral groups within the cupulate or
shoe-shaped cyathium; cyathia often in cymose or dichotomous inflorescences; caruncle small or
absent; herbs, shrubs, or small trees; sap usually whitish (often caustic) 47
38a. Inflorescences thyrsoid or paniculate (resembling racemes in Mabea); $ flowers with anthers subsessile on an elevated receptacle 39
38b. Inflorescences spicate or racemose; $ flowers with anthers borne on well-developed filaments
. 40
BURGER & HUFT: FLORA COSTARICENSIS
39a. Trichomes branched (dendritic); 2 flower with long stylar column; <3 flowers 2 or more/ node, long-pedicellate, stamens 10 or more in our species [inflorescences long and
racemose] Mabea
39b. Trichomes absent, plants glabrous; 2 flower with styles nearly free to the base; $ flowers I/node, subsessile, stamens 5 [eastern Panama and South America; not included in
text] Senfeldera
40a. Stylar column at least 25 mm long, terminated by a fleshy disk 2-3 cm wide and resembling a parasol; <5 flowers breaking their perianth irregularly in early anthesis, with anthers borne in whorls on cone-like columns from the axis of the inflorescence; ovary and fruit with more
than 10 locules [capsule 5-9 cm diam.J Hura
40b. Stylar column < 25 mm long, styles diverging distally and not forming a flat disk; $ flowers not rupturing the perianth and not borne on conical projections of the inflorescence axis;
ovary and fruit with fewer than 1 0 locules 41
4 la. Ovary 6-9-locular; fruits drupaceous and not splitting open [seeds lacking a caruncule; 2 flowers with 3-parted calyx; petiole with single gland; latex extremely caustic; seaside trees]
Hippomane
41b. Ovary 2-3-locular; capsules often splitting open explosively 42
42a. Seeds lacking a caruncle, seed coat fleshy; petioles usually with a pair of cylindrical glands;
2 sepals united at the base [6 flowers with 2 stamens] Sapium
42b. Seeds with a caruncle, seed coat dry; petioles without prominent glands; 2 flowers with separate
sepals 43
43a. Dehisced fruits with persistent woody 3-pronged stylobase (gynobase), columella present or absent; stems usually with much white sap; leaf blades with paired glands near the base [seeds
with small caruncle in Central American species, rare in our area] Stillingia
43b. Dehisced fruits without a persisting woody 3-pronged stylobase, columella usually present;
stems with little or no white sap; leaf blades without stalked glands 44
44a. $ part of the inflorescence contracted to less than 1 cm long and ovoid; stamens 2 with filaments united, styles distinctly connate; seeds with large cap-like caruncle, seed surface
foveolate [central Panama to South America and not included in text] Maprounea
44b. <3 part of the inflorescence elongated and spicate, not contracted and subglobose; stamens usually 3-5, filaments free or partly connate; styles free or partly united in Actinostemon;
seeds with small caruncle, seed coat smooth 45
45a. Spikes terminal or opposite the leaves; <3 calyx 3-lobed, stamens 3; ovary with 3 or 6 distal
lobes or projections; fruiting pedicels < 5 mm long Sebastiania
45b. Spikes or racemes axillary or pseudoaxillary; 6 calyx minute and 1 -parted or absent; stamens
2-6 (in Costa Rica); ovary smooth; fruiting pedicels > 1 0 mm long 46
46a. Stipules and bud-scales < 1 mm long, not forming cap-like structures over shoot-apices and
early inflorescences, often persisting; inflorescences minutely puberulent or glabrous
Gymnanthes
46b. Stipules and bud-scales ca. 3 mm long, often forming a cap over shoot-apices and early
inflorescence-buds, caducous; inflorescences essentially glabrous Actinostemon
47a. (from 37b) Cyathia (flower-like pseudanthia) bilaterally symmetrical with involucre somewhat shoe-shaped, often with reddish coloring; involucral glands borne within the nectar spur and not
visible from the exterior; styles connate into a long column; distal stems often green
Pedilanthus
47b. Cyathia radially symmetrical, involucre usually urceolate or campanulate and round in cross- section, usually greenish, yellow or white; involucral glands usually visible at the edge of the involucral cup; styles not forming a long column; distal stems green or woody and brown ... 48 48a. Involucre without 4-5 distinct glands alternating with lobes of the cyathium, involucre usually
saucer-shaped, red; few-branched succulent ornamental shrubs Synadenium
48b. Involucre usually with 4-5 (1-3) distinct glands alternating with the lobes on the rim of the cyathium, involucre usually deeply cupulate or urceolate; trees, shrubs, and herbs, succulent or
not, cultivated and wild 49
49a. Leaves alternate, opposite or whorled, if opposite then blades not asymmetric at the base; stipules
FIELDIANA: BOTANY
absent or gland-like and small; veins of the leaf blades lacking a sheath of chlorenchyma; main
axis of the plant not aborting soon after germination; trees, shrubs, or herbs Euphorbia
49b. Leaves always opposite, blades usually small and strongly asymmetric at the base; stipules present and often lobed; veins of the leaf blades with a sheath of chlorenchyma (in dried leaves the veins often look translucent in transmitted light, in contrast to the darker areas between the veins); main axis of the young plant aborting just above the cotyledons; herbs and small shrubs Chamaesyce
Key 2: Artificial Key to Genera and Unusual Species
la. Leaves compound with usually 3 leaflets, or the leaves simple and with prominent lobes > 20%
the length or width of the leaf blade 2
Ib. Leaves simple and without prominent lobes, the blades entire to deeply serrate, dentate or crenate, teeth or lobes < 1 5% the width of the blades (note: simple leaves usually have buds or flowers in
the axils of their petioles but leaflets do not) 16
2a. Leaves 3-foliolate, petioles with 3 petiolate leaflets at the apex in at least some of the leaves
on the plant 3
2b. Leaves simple, petioles with a single leaf blade (the leaf blade may be deeply divided but
the divisions do not have slender petiolules at their base) 4
3a. Slender-stemmed vines; leaves sometimes simple and compound on the same stem;
native Dalechampia spp.
3b. Trees; leaves always 3-foliolate; introduced economically useful plants
Hevea brasiliensis
4a. Venation pinnate, lobes and sinuses along the lateral margins of the leaves 5
4b. Venation palmate, lobes and sinuses distal and lateral on the leaf margin 6
5a. Weedy herbs to 1 m tall Euphorbia heterophylla
5b. Garden shrubs to 5 m tall Codiaeum variegatum
6a. Leaf blades peltate, petiole attached near the center or near the edge of the blade 7
6b. Leaves with the petioles attached at the edge of the blade 8
7a. Margin of the leaf serrate; petiole attached near the center of the blade
Ricinus communis
7b. Margin of the leaf entire; petiole attached near the edge of the blade . . . Jatropha spp. 8a. Plants slender vines with clambering branches, stems becoming > 1 m long, leaves > 4 cm
long 9
8b. Plants erect herbs, trees, and shrubs, or if prostrate or procumbent and clambering the stems
< 1 m long with leaves usually < 3 cm long 11
9a. Plants without stinging hairs; inflorescences racemose with prominent pedicels (to 1 5
mm long); flowers 6-18 mm long with prominent 5-lobed or 5-parted perianth
Manihot brachyloba
9b. Plants often with stinging hairs (at least near the flowers); inflorescences not clearly racemose; flowers lacking prominent calyx 6-18 mm long, often subtended by 2 large
perianth-like bracts 10
lOa. Inflorescences with 1 or 2 slender axes from a peduncle 1-10 cm long, floral bracts 3-
5 mm long, many along the axes Tragia bailloniana
lOb. Inflorescences flower-like with 2 large (1-6 cm) floral bracts usually held in a vertical
plane (subtending the flowers) Dalechampia spp.
11 a. Stinging hairs usually present (around the flowers if lacking on the stems) [inflorescences
usually dichotomously branched] Cnidosculus spp.
lib. Stinging hairs absent 12
12a. Trees with broad (8-30 cm) leaves and short (1-5 cm) triangular obtuse lobes, depth of
sinuses between lobes < 25% of the blade length 13
1 2b. Herbs, shrubs, small trees, or vines, leaves small to broad (3-25 cm) and with narrow lobes,
depth of sinuses > 30% of the length of the blade 14
1 3a. Apex of the petiole with prominent glands, stellate and scurfy hairs present; native forest trees . . . Croton smithianus
BURGER & HUFT: FLORA COSTARICENSIS
1 3b. Apex of the petiole without prominent glands, plants glabrous or with simple or scurfy
hairs; introduced trees Aleurites spp.
14a. Stems with stellate hairs; inflorescences lacking lateral branches; herbs to 1 m tall; leaf blades
3-9 cm long Croton lobatus
14b. Stems lacking stellate hairs, glabrous or with glandular hairs; inflorescences often with short
lateral branches; herbs, shrubs, small trees, or vines, leaf blades 5-25 cm long 15
15a. Stems usually glabrous or with hairs less than 0.3 mm long; flowers with a single perianth- like whorl, united in the lower part in <3 flowers; small shrubs, small trees, or vines
Manihot spp.
1 5b. Stems usually puberulent, often with gland-tipped hairs; flowers with 2 whorls of free sepals
and petals; herbs, shrubs, or trees Jatropha spp.
1 6a. (from 1 b) Plants slender vines with twining branches, shrubs with clambering green stems or woody
lianas, stems becoming > 1 m long, leaves > 4 cm long 17
1 6b. Plants erect herbs, trees, and shrubs, or if prostrate or procumbent and clambering then the stems
< 1 m long with leaves usually < 3 cm long 21
1 7a. Plants becoming woody lianas with stems usually > 4 mm thick [inflorescences 1 5-50 cm long, paniculate; leaves often subcoriaceous, 6-24 cm long, palmately veined; stinging hairs
absent] Omphalea diandra
17b. Plants not becoming thick-stemmed woody lianas, leafy stems usually < 4 mm thick ... 18
1 8a. Shrubby plants with clambering terete green branches ca. 3-10 mm thick, sap white; stinging
hairs absent; flowers (= pseudanthia) bilaterally symmetrical and shoe-shaped, orange or red
[gardens and seasonally dry habitats] Pedilanthus
1 8b. Vines, not shrub-like, climbing leafy stems usually < 4 mm thick; flowers not shoe-shaped
19
19a. Inflorescences flower-like with 2 prominent bracts usually held in a vertical plane and en- closing unusual flowers; venation palmate [stinging hairs sometimes present]
Dalechampia spp.
19b. Inflorescences not flower-like, bracts not large (> 5 mm wide) or opposite in a single plane;
venation palmate or pinnate 20
20a. Stinging hairs usually present; inflorescences terminal or leaf-opposed, with 1 or 2 slender
unbranched axes; styles united only at base, fruit usually 3-locular Tragia spp.
20b. Stinging hairs absent; inflorescences axillary or terminal with 1 stiff rachis; styles united into
a thick column, fruit usually 4-locular Plukenetia spp.
2 la. (from 1 6b) Leaf blades consistently < 5 cm long 22
2 1 b. Larger leaf blades > 5 cm long 27
22a. Leaf blades consistently opposite along the stems 23
22b. Leaf blades alternate along the stems, but sometimes opposite below the inflorescences and/
or at branching nodes 24
23a. Leaf blades usually strongly asymmetrical (unequal) at the base, often very small (5- 1 5 mm) stipules laciniate to ovate; plants erect or prostrate, herbs and subshrubs . . .
Chamaesyce spp.
23b. Leaf blades symmetrical (equal) at the base, usually > 10 mm long; stipules usually
poorly developed; plants erect herbs, shrubs, or trees Euphorbia spp.
24a. Fruits with 2 seeds/locule, seeds wedge-shaped and acutely triangular in cross-section; flowers few from the leaf axils, subtending bracts inconspicuous; leaf blades often in a single plane, very small to large (5-50 mm long) [note that cultivated ornamental shrubs with rounded
variegated leaves keying here are Breynia disticha] Phyllanthus spp.
24b. Fruits with 1 seed/locule, seeds rounded or angular in cross-section; flowers few to many, axillary, terminal or extra-axillary, usually with conspicuous bracts; leaves usually in a spiral,
rarely < 1 5 mm long 25
25a. Stems slender and repent; herbs at high (2000-3000 m) elevation [leaves ovate-orbicular
with rounded crenate margins] Dysopsis glechomoides
25b. Stems not slender and creeping, mostly erect; plants rarely found above 2000 m elevation
. 26
FIELDIANA: BOTANY
26a. Male spikes leaf-opposed; female flowers often on stems between the nodes; fruits subtended
by sepals with scale-like processes on the outer surfaces; small-leaved herbs, rarely collected
in Central America Sebastiania corniculata
26b. Plants without the above characteristics 27
27a. (from 2 Ib and 26b) Weak-stemmed herbs and subshrubs 28
27b. Shrubs and trees with strong erect woody stems 32
28a. Leaf blades entire, glabrous or with thin inconspicuous hairs; sap often whitish; flowers
(actually pseudanthia) with calyx-like cup; pistil borne on an articulated stipe within the cup
Euphorbia spp.
28b. Leaf blades serrate to crenate, densely pubescent when subentire; sap rarely whitish; flowers
without calyx cups or urceolate perianth tube; pistils sessile 29
29a. Inflorescences terminal and spicate, resembling a foxtail or Cenchrus inflorescence, or the 2
flowers subtended by broadly rounded bracts with toothed margins and enlarging in fruit;
style branches usually much divided and laciniate Acalypha spp.
29b. Inflorescences not resembling foxtails, bracts subtending the fruit not broadly rounded and
exceeding the fruit in size; style branches not laciniate 30
30a. Plant usually growing in water or at the edge of wet sites, main stems usually hollow; venation
pinnate with 5-20 pairs of 2° veins [petioles without stalked glands or stipels at the apex,
base of blade without glands, blades ovate to linear-lanceolate] Caperonia spp.
30b. Plants not usually growing in or near water, main stems solid; venation usually palmate with
fewer than 6 pairs of 2° veins 31
3 la. Stellate or peltate hairs often present, simple hairs not attached at the center when present;
stalked glands often present at apex of the petiole; $ flowers with stamens inflexed in bud
Croton spp.
3 1 b. Hairs attached at the center but often appearing simple and appressed, stellate and peltate
hairs absent, stipel-like structures usually present at the apex of the petiole; $ flowers with
stamens straight in bud Argythamnia guatemalensis
32a. (from 27b) Ornamental small trees and shrubs cultivated in gardens and parks; leaves green to
red, purple, yellowish, or whitish; some with thick succulent green stems 33
32b. Plants not grown as ornamentals, wild species but sometimes used as hedges; leaves not brightly
colored; none with thick succulent green stems 39
33a. Leaf blades distinctly serrate, often reddish to copper colored; inflorescences pendant, to 40
cm long with reddish fimbriate style branches Acalypha spp.
33b. Leaf blades entire to subentire, green to purple, yellow, marked with white or leaves absent
and the stems green 34
34a. Leaf blades usually 3-5 times longer than wide, often variegated with yellow, green, white,
and purple, margins often undulate, sinuate, or minutely denticulate [few-branched shrubs]
35
34b. Leaf blades 1-3 times longer than wide, variegated leaves present or absent, margins entire
or sinuate 36
35a. Stems woody and without white sap; leaf blades subcoriaceous; inflorescences un- branched and yellowish Codiaeum variegatum
35b. Stems semisucculent and with whitish sap; leaf blades slightly succulent; inflorescences
with dichotomous branches, reddish Synadenium grantii
36a. Fruits sweet fleshy drupes, 1 -seeded; leaves subcoriaceous and entire; sap not white or caustic;
shrubs or subshrubs Antidesma bunius
36b. Fruits dry capsules, usually 3-seeded; leaves thin to semisucculent; sap often white and caustic;
shrubs, trees, or green-stemmed vines and succulents 37
37a. Flowers (actually cyathia) shoe-shaped and bilaterally symmetrical, reddish or orange [petals
absent; distal stems green and terete and often clambering; plants to 2 m tall]
Pedilanthus spp.
37b. Flowers not shoe-shaped, radially symmetrical, white, yellow, red, or greenish 38
38a. Flowers (actually cyathia) urceolate or campanulate, greenish to yellow or red, petal-like
BURGER & HUFT: FLORA COSTARICENSIS
appendages small or absent; distal stems green and terete or woody; some plants resembling cacti, others leafy trees and shrubs Euphorbia spp.
38b. Flowers with separate petals and sepals, not urceolate or campanulate, petals often large and
colorful; small trees and shrubs, not cactus-like Jatropha spp.
39a. (from 32b) Larger leaf blades rounded at the base and cordate to subcordate 40
39b. Larger leaf blades acute to obtuse or truncated at the base, not cordate or subcordate 44
40a. Plants becoming large trees with broad-based conical spines on the grayish trunk; fruit ca. 6
cm diam. with ca. 15 locules and seeds; staminal column with 2 (3) whorls of sessile anthers
Hura crepitans
40b. Plants shrubs or small to large trees, trunks lacking spines; fruits < 3 cm diam. with ca. 3 locules and seeds; stamens not united into a single column with whorled anthers 41
4 la. Style branches much divided and fimbriate; $ flower buds < 1 mm diam., anthers < 0.2 mm wide; fruits often subtended by a large broad bract Acalypha spp.
41b. Style branches simple to 2 times bifid, not fimbriate or laciniate; $ flower buds ca. 2 mm diam., anthers > 0.2 mm wide; fruits not subtended by a broad bract 42
42a. Stamens incurved in bud, mostly 8-30/flower; petioles usually with stalked glands at apex; stellate, scurfy or peltate hairs often present; inflorescences always with a single unbranched rachis Croton spp.
42b. Stamens straight in bud, 3-5 or 30-60/flower; petioles without stalked glands at apex but
stipels may be present; hairs simple or stellate; inflorescences unbranched or paniculate . .
43
43a. Minute stellate hairs present on the leaf abaxially; $ flowers with 30-60 stamens; fruits fleshy ca. 1 8 mm long, oblong; tall trees Conceveiba pleiostemona
43b. Small straight hairs present on the leaf surfaces; $ flowers with 3-5 stamens; fruits dry capsules
ca. 7 mm long; small trees Aparisthmium cordatum
44a. (from 39b) Leaf blades with palmate venation, the basal pair of lateral (2°) veins reaching the
middle or distal half of the blade 45
44b. Leaf blades with pinnate venation, the basal pair of lateral (2°) veins not reaching the distal half
of the blade 48
45a. Leaves usually tripliveined, the basal pair of veins strongly ascending and reaching the distal third of the blade, midvein with only 1 pair of additional prominent 2° veins, pit domatia
often present in the vein axils [6 inflorescences unbranched; fruits ca. 4 mm diam.]
Alchorneopsis floribunda
45b. Leaves rarely tripliveined (except in Alchorned), the midvein usually with 2 or more pairs of prominent 2° veins, pit domatia rarely present 46
46a. Style branches much divided and fimbriate; 3 flower buds < 1 mm diam., anthers < 0.2 mm long; fruits often subtended by a large broad bract Acalypha spp.
46b. Style branches simple to 2 times bifid, not fimbriate or laciniate; <3 flower buds 2-5 mm diam., anthers > 0.3 mm long; fruits not subtended by a broad bract 47
47a. Stamens incurved in bud, 8-50/flower; fruits usually 3-locular; style branches usually 3- many; inflorescences with a single unbranched rachis (except in C. billbergianus); petioles
often with stalked glands at apex; stellate, scurfy or peltate hairs often present
Croton spp.
47b. Stamens straight in bud, usually 8/flower; fruits usually 2-locular; style branches usually 2; inflorescences unbranched or paniculate; petioles without stalked glands at apex but 2-6 flat
glands often present in the base of the blade; hairs simple or stellate Alchornea spp.
48a. (from 44b) Larger leaf blades with more than 10 major secondary veins on each side 49
48b. Larger leaf blades usually with fewer than 10 major secondary veins on each side 54
49a. Petioles with elevated glands along their length or at the apex (sometimes absent or at the base of the blade, be sure to survey a number of leaves); flowers sessile or short-pedicellate and the inflorescence spicate 50
49b. Petioles without elevated glands; flowers on prominent pedicels and the inflorescences rac- emose 52
50a. Leaves narrowly obovate, 1 8-70 cm long [margin with conspicuous gland-tipped teeth];
10 FIELDIANA: BOTANY
hairs attached at the center; inflorescences axillary; <5 bracts small, 9 floral bracts with
glands ca. 1 mm diam Pausandra trianae
50b. Leaves oblong to elliptic oblong, 6-20 (rarely to 26) cm long; hairs attached at base or leaves glabrous; inflorescences mostly terminal, floral bracts with broad rounded sessile
flat glands 1 .2-3 mm wide 51
5 la. Common trees; leaves 2-9 cm wide; leaf margin entire or rarely serrulate, the teeth
without prominent glands at their apex Sapium spp.
51b. Shrubs (rare in our area); leaves 0.7-3(-4) cm wide, leaf margins serrate with gland- tipped teeth Stillingia zelayensis
52a. Flowers in dense cymes on dichotomously branching inflorescences or crowded in leaf axils; flowers (pseudanthia) with calyx-like cup or tube; leaf margins always entire; small shrubs
to small trees Euphorbia spp.
52b. Flowers in open racemose inflorescences with a single unbranched rachis; flowers without a
cup-like or tubular calyx; leaf margins entire or dentate; shrubs to tall trees 53
53a. Trees and shrubs, usually with both $ and 2 flowers; inflorescences 10-40 cm long with many closely crowded flowers; petals absent; anthers sessile on a conical receptacle; leaves usually
narrowly oblong, serrulate Mabea spp.
53b. Trees dioecious (unisexual); inflorescences 3-12 cm long with well-separated flowers; petals present; anthers borne on slender filaments in <5 flowers; leaves usually elliptic-oblong, entire
Sagotia racemosa
54a. (from 48b) Styles much divided and laciniate, with slender filamentous divisions; fruit usually subtended by broad serrate bracts; anthers usually < 0.2 mm wide; inflorescences usually narrow spikes and racemes (the 9 inflorescence pyramidal-paniculate with slender lateral branches and the fruit not subtended by broad bracts in A. costaricensis); trichomes of simple hairs attached at the
base; leaf margins serrate Acalypha spp.
54b. Styles not divided into slender filamentous divisions (except in Adelia with tufted domatia in leaf axils); fruits not subtended by broad serrate bracts; anthers > 0.2 mm wide; inflorescences and
trichomes various; leaf blades entire to serrate 55
55a. Stalked or prominent glands usually present at the apex of the petiole or base of leaf blade; hairs stellate, scurfy, peltate (flat and rounded) or simple; inflorescences with a single unbranched rachis; $ flowers with well-developed perianth, the 8-40 stamens incurved in bud; 9 flowers with style branches usually bifid or twice bifid; fruits dry 3-seeded capsules; seeds with a smooth surface and
apical caruncle Croton spp.
55b. Plants without the above suite of characteristics 56
56a. Young leafy stems or leaves with flat rounded hairs, the small (ca. 0.2 mm) appressed hairs (peltate trichomes) often difficult to see [plants unisexual; fruits often with a slightly fleshy covering] 57
56b. Young leafy stems lacking flat appressed rounded hairs 58
57a. Fruits 3-6 mm long, with a single seed; inflorescences paniculate, usually with few spiciform
branches, never globose in bud Hyeronima spp.
57b. Fruits 12-14 mm long, with 3 seeds; inflorescences with few flowers from a short common
peduncule, at first enclosed in rounded bracts and resembling a flower bud . . Pera arborea
58a. Petioles with raised glands at the apex or along their length, or with raised glands at the base of
the blade 59
58b. Petioles without raised glands, flat or rounded glands sometimes present at the base of the blade
or along the blade margins 63
59a. Flowers borne on long (8-50 mm) thin pedicels from the axils of leaves [leaves entire and
ovate-rhombic; rarely collected in Costa Rica] Astrocasia tremula
59b. Flowers borne on axes of inflorescences, flowers sessile or on short thick pedicels [often associated with 2 glands; 6 flowers with 2-3 stamens but the flowers often crowded and
difficult to interpret] 60
60a. Leaves glabrous or with appressed straight hairs attached at the middle; plants unisexual (dioecious); flower groups often on short (1-3 mm) lateral peduncles [inflorescences with floral glands not appressed on the rachis; fruits capsules] Tetrorchidium spp.
BURGER & HUFT: FLORA COSTARICENSIS 1 1
60b. Leaves usually glabrous, hairs attached at the base if present; plants bisexual (monoecious);
flower groups usually sessile or subsessile on the rachis 61
6 1 a. Fruits fleshy and green, usually with more than 4 seeds; sap highly caustic; leaf blades rounded- ovate; trees of ocean shores and swamps Hippomane mancinella
61b. Fruits dry capsules with 3 or fewer seeds; sap not caustic; leaf blades ellipsoid to oblong;
trees of varied habitats 62
62a. Glands on the petiole apex or in the middle, prominent and easily seen; floral glands flat, 1.5-3 mm long, rounded and appressed on the inflorescence rachis; leaves mostly thick and
oblong Sapium spp.
62b. Glands at the base of the blade small and often difficult to see; floral glands less than 1 mm diam., borne on the floral bracts; leaves mostly thin and elliptic . . Sebastiania pavoniana
63a. Leaf blades entire, the margins entire and lacking glands 64
63b. Leaf blades minutely serrate to conspicuously dentate or rounded-crenate, with well-defined glands
along the margin if subentire 72
64a. Petiole distinctly thickened below the blade for 4-8 mm and terete [inflorescences of 1-few terminal flowers; $ flowers ca. 3 cm wide with many stamens; fruits 3—4 cm diam.; seasonally
dry forests] Garcia nutans
64b. Petioles without a prolonged thickened terete area beneath the blade, a short thickened area
at the apex of the petiole sometimes present 65
65a. Leaf blades with a notch (indentation) and terminal gland at the apex [blades elliptic-oblong with a narrowed apex; inflorescences terminal with a few thick spiciform branches; rarely
collected in southern Central America] Caryodendron angustifoliwn
65b. Leaf blades lacking a notch and terminal gland at the apex 66
66a. Fruits 1 -seeded and with a thin fleshy cover; unisexual (dioecious) trees [ovary with 2 ovules/
locule but only 1 ovule developing; leaves subcoriaceous] 67
66b. Fruits usually 3-seeded, dry or with a thin fleshy covering; unisexual or bisexual, trees or
shrubs 68
67a. Leaf blades elliptic to oblong, often asymmetric at the base; flowers borne in leaf axils
on short or long pedicels; fruits axillary, seeds without a red or orange aril
Drypetes spp.
67b. Leaf blades often obovate, symmetric at the base; flowers and fruits borne on spikes or racemes with thick axes; pedicels short or flowers sessile; seeds with red or orange
aril Richeria obovata
68a. Ovules 2 in each locule, fruits usually with 4-6 seeds; leaves usually distichous; flowers on
thin pedicels in axillary fascicles 69
68b. Ovules 1 in each locule, fruits usually 2-3-seeded; leaves usually in a spiral; flowers borne
on short racemes, in cymose groups, or in axillary fascicles 70
69a. Plants unisexual (dioecious); leaves deciduous; $ flowers with 4 stamens; fruits 9-12
mm diam., seeds 3-5 mm long, with fleshy bluish covering; a common species
Margaritaria nobilis
69b. Plants bisexual; leaves evergreen; <5 flowers with 3 stamens; fruits ca. 8 mm diam., seeds
ca. 7 mm long, without a fleshy covering; rarely collected Phyllanthus skutchii
70a. Flowers without perianth, borne on short (4 cm) unbranched axillary racemes [leaves narrowly
obovate and subcoriaceous] Actinostemon caribaeus
70b. Flowers with 4-5 sepals, or with a cupulate or urceolate base resembling a calyx cup ..71 7 la. Flowers with 4-5 distinct sepals, without a calyx cup; flowers borne in axillary fascicles; fruits
pendulous on long slender pedicels; leaves with tufted domatia in vein axils beneath
Adelia triloba
7 1 b. Flowers (pseudanthia) with a cupulate or urceolate base resembling a calyx cup, usually borne in cymes; fruit never pendulous on long pedicels; leaves without tufted domatia in vein axils
Euphorbia spp.
72a. (from 63b) Stipules persisting, triangular to lanceolate, with 3-7 prominent raised veins parallel with the midrib; stinging hairs present or absent 73
12 FIELDIANA: BOTANY
72b. Stipules caducous or, if persisting, without prominent parallel venation; stinging hairs absent . .
74
73a. Shrubs or small treelets 1-7 m tall; leaves with prominent distal serrations, 8-18 cm long; stinging hairs usually present on the anther tips and fruits and sometimes on the leaves . .
Acidoton nicaraguensis
73b. Small single-stemmed subshrubs to 1 m tall; leaves subentire to serrulate, 12-28 cm long;
stinging hairs usually absent Dalechampia spathulata
74a. Inflorescences 12—45 cm long, racemose with a single axis and long-pedicellate flowers; $ flowers
with subsessile anthers on a conical receptacle [leaf blades oblong to narrowly oblong]
Mabea occidentalis
74b. Inflorescences not 12-45 cm long and racemose; anthers on a dome-shaped conical androecium
only in Cleidion (with inflorescences < 12 cm long) 75
75a. Leaves with small stellate hairs on the upper (adaxial) surface; $ inflorescences with overlapping
pubescent bracts, catkin-like in leaf axils [fruits 7xll mm; leaf blades 3-12 cm long]
Bernardia nicaraguensis
75b. Leaves glabrous on the upper surface or with few simple hairs; $ inflorescences of congested flowers
in sessile glomerules on slender spikes 76
76a. Leaves with petioles 13-50 mm long, distinctly thickened at the apex and often slightly bent [leaf
margins with prominent gland-tipped teeth] 77
76b. Leaves with petioles 4-16 mm long, not clearly thickened or bent at the apex [$ flowers usually
with 3 stamens] 78
77a. Styles usually 2 and simple; fruits with usually 2 seeds and fleshy exterior; 6 flowers usually
with 8 stamens; young stems glabrous Alchornea spp.
77b. Styles usually 3 and bifid; fruits dry capsules with usually 3 seeds; $ flowers with ca. 30
stamens on a conical receptacle; young stems minutely puberulent
Cleidion castaneifolium
78a. Leaves 12-33 cm long, often oblanceolate; plants unisexual; $ flowers with 3 sepals, 2 flowers with
6 sepals in 2 whorls, style branches broad Adenophaedra grandifolia
78b. Leaves 6-16(-20) cm long, usually obovate; plants usually bisexual; flowers with 0-2 bract-like perianth parts, style branches slender Gymnanthes riparia
BURGER & HUFT: FLORA COSTARICENSIS 13
Manihot aesculifolia
FIG. 1 . Shrubs or treelets with deeply lobed leaves: species of Manihot and Ricinus.
14
FIELDIANA: BOTANY
Cnidoscolus aconitifolius
FIG. 2. Vines and subshrubs with lobed leaves: species of Croton, Cnidoscolus, and Tragia.
BURGER & HUFT: FLORA COSTARICENSIS
15
J. curcas
FIG. 3. Trees and shrubs with deeply to slightly lobed leaves with palmate venation: species ofJatropha.
16
FIELDIANA: BOTANY
I 10cm
FIG. 4. Slender-stemmed vines with lobed or compound leaves: species of Dalechampia.
BURGER & HUFT: FLORA COSTARICENSIS
17
Tragia volubilis
Tr. correae
Tragia bailloniana
Dalechampia
>
heteromorpha
FIG. 5. Slender-stemmed vines: species of Dalechampia, Plukenetia, and Tragia.
18
FIELDIANA: BOTANY
Cnamaesyce serpens
Chamaesyce thymifolia
5 mm
Chamaesyce dioica
FIG. 6. Plants with very small leaves: species of Chamaesyce and Euphorbia.
BURGER & HUFT: FLORA COSTARICENSIS
19
Chamaesyce bahiensis
C. mesembrianthemifolia
FIG. 7. Plants with small opposite leaves: species of Chamaesyce.
20
FIELDIANA: BOTANY
Phyllanthus stipulatus
Phyllanthus amarus
P. niruri
Phyllanthus hyssopifolioides
1 mm
P. compressus
P. caroliniensis
FIG. 8. Plants with small alternate leaves: species of Phyllanthus.
BURGER & HUFT: FLORA COSTARICENSIS
21
Phyllanthus valerii
P. mocinianus
P. mocinianus s.l. (P. anisolobus s.s.)
FIG. 9. Plants with small alternate leaves: species of Phyllanthus.
22
FIELDIANA: BOTANY
Dysopsis glechomoides
10 cm
Caperonia castaneifolia
FIG. 10. Herbaceous or weedy plants: species of Caperonia, Croton, and Dysopsis.
BURGER & HUFT: FLORA COSTARICENSIS
23
Sebastiania corniculata
Argythamnia guatemalensis
FIG. 1 1. Herbaceous or weedy plants: species ofAcalypha, Argythamnia, and Sebastiania.
24
FIELDIANA: BOTANY
Bernardia
Acidoton nicaraguen'sis
Alchornea costaricensis
Cleidion castaneifolium
FIG. 12. Trees and shrubs with serrate elliptic leaves: species of Acidoton, Alchornea, Bernardia, Cleidion, Croton, and Gymnanthes.
BURGER & HUFT: FLORA COSTARICENSIS
25
Pausandra trianae
Adenopnaedra grandifolia
Dalechampia spathulata
FIG. 13. Plants with larger oblanceolate serrate leaves: species of Adenophaedra, Dalechampia, and Pausandra.
26
FIELDIANA: BOTANY
FIG. 14. Shrubs or herbs with serrate leaves and laciniate styles: species of Acalypha.
BURGER & HUFT: FLORA COSTARICENSIS
27
Acalypha macrostachya
A. costaricensis
FIG. 15. Shrubs with serrate leaves and laciniate styles: species of Acalypha.
28
FIELDIANA: BOTANY
C. yucatanensis
FIG. 16. Plants with slightly serrate leaves and stellate hairs: species of Croton. BURGER & HUFT: FLORA COSTARICENSIS
29
FIG. 1 7. Trees and shrubs with flat peltate hairs: species of Croton.
30
FIELDIANA: BOTANY
Croton xalapensis
FIG. 18. Trees and shrubs with larger ovate leaves, stellate hairs, and glands at apex of petiole: species of Croton.
BURGER & HUFT: FLORA COSTARICENSIS
31
Croton tenuicaudatus
5 mm
FIG. 19. Trees and shrubs with larger ovate or oblong leaves and stellate or peltate hairs: species of Croton.
32
FTELDIANA: BOTANY
Aparisthmium cordatum
Conceveiba pleiostemona
Tetrorchidium euryphyllum
FIG. 20. Trees with larger leaves: species of Aparisthmium, Conceveiba, Sagotia, and Tetrorchidium. BURGER & HUFT: FLORA COSTARICENSIS 33
Tetrorchidium euryphyllum
FIG. 2 1 . Trees with glands on petioles or a thickened petiole apex: species of Garcia and Tetrorchidium.
34
FIELDIANA: BOTANY
Sapium glandulosum sensu lato
FIG. 22. Trees with glands on petioles: species of Sapium.
BURGER & HUFT: FLORA COSTARICENSIS
35
Sapium glandulosum (montane forms)
Sapium rigidifoiium
10 cm
FIG. 23. Trees with glands on petioles (Sapium spp.) or shrubs with glands along lamina margins (Stillingia sp.).
36
FIELDIANA: BOTANY
Alchorneopsis floribunda
FIG. 24. Trees with slightly serrate leaves and subpalmate or palmate venation: species of Alchornea and Al- chorneopsis.
BURGER & HUFT: FLORA COSTARICENSIS
37
Sebastiania pavoniana
Actinostemon caribaeus
Margaritaria nobilis
FIG. 25. Trees and shrubs with entire or subserrate leaves: species of Actinostemon, Margaritaria, Phyllanthus, and Sebastiania.
38
FIELDIANA: BOTANY
Gymnanthes lucida Gymnanthes riparia
FIG. 26. Trees and shrubs with entire elliptic leaves: species of Gymnanthes, Mabea, and Pera.
BURGER & HUFT: FLORA COSTARICENSIS
39
Drypetes standleyi
UB
Drypetes brownii
Amanoa guianensis
FIG. 27. Trees and shrubs with entire elliptic leaves: species of Amanoa and Drypetes.
40
FIELDIANA: BOTANY
Hyeronima alchorneoides
FIG. 28. Trees with spicate inflorescences or inflorescence branches: species of Hyeronima and Richeria.
BURGER & HUFT: FLORA COSTARICENSIS
41
Euphorbia heterophylla
UB
Euphorbia oerstediana
FIG. 29. Herbs or weak-stemmed shrubs with entire leaves and white sap: species of Euphorbia.
42
FIELDIANA: BOTANY
Euphorbia hoffmanniana
Euphorbia colletioides
Euphorbia schlechtendalii
GJB
FIG. 30. Shrubs and trees with small entire leaves and white sap: species of Euphorbia.
BURGER & HUFT: FLORA COSTARICENSIS
43
Plukenetia penninervia
Adelia triloba
cm
FIG. 31. Climbers and unusual plants: species of Adelia, Mabea, Omphalea, and Plukenetia.
FIELDIANA: BOTANY
Hippomane mancinella
Codiaeum vanegatum
FIG. 32. Trees and shrubs with distinctive leaves: species of Astrocasia, Codiaeum, Hippomane, and Hura.
BURGER & HUFT: FLORA COSTARICENSIS
45
Descriptions of Genera and Species
Acalypha Linnaeus
REFERENCE— O. Seberg, Taxonomy and phylog- eny of the genus Acalypha (Euphorbiaceae) in the Galapagos Archipelago. Nord. J. Bot. 4: 159-190. 1984.
Annual or perennial herbs, shrubs or small trees, mo- noecious or less often dioecious, hairs simple or stellate (plants rarely glabrous); stipules paired at the leaf base, ovate to lanceolate or linear, (l-)3-7- veined, often with linear distal awn. Leaves alternate, simple, petiolate, glands absent at apex of petiole (stipels rarely present); leaf blades mostly ovate, palmately 3-5-veined or pin- nately veined, pubescent or glabrous, margins crenate- serrate or dentate (not lobed). Inflorescences terminal or axillary, unisexual or bisexual, solitary, the 3 axillary (often below the 9) usually spiciform and slender with flowers in sessile clusters; 2 inflorescences axillary or terminal, open paniculate to spicate or racemose, bisex- ual spikes usually with 9 flowers proximal and <5 distal, floral bracts broadly sessile, often enlarging and enclosing the fruit; 9 flowers sessile or short-pedicellate. Male flow- ers very small, pedicellate, globose in bud, calyx 4-parted, valvate in bud, petals absent, disk absent, stamens 8 (4, -16), borne on a slightly raised receptacle, filaments free, anthers with divaricate or pendulous thecae, oblong or linear to vermiform; pistillode absent. Female flowers with 3-5 sepals, united at or near the base, imbricate or open in bud, shorter than the pistil, petals absent, stam- inodes absent, disk absent; ovary 3-(2-)locular, surface often muricate, pubescent or papillate, ovules 1/locule,
style column short, each style with many slender lacin- iate style branches (unbranched in A. alopecuroided). Fruits capsular, usually small, 3-lobed and breaking into 3 2-valved 1 -seeded cocci, bracts enlarging in fruit (in most species) to envelop the capsule; seeds small, ellip- soid to subglobose, caruncle minute or absent, testa crus- taceous, endosperm fleshy or granular, cotyledons broad and flat.
A pantropical genus of 400-500 species with a few species reaching temperate regions. The ma- jority of species are Neotropical and are in serious need of monographic study. Many species are weedy plants of open sites that vary greatly from individual to individual. This large intraspecific variation has made understanding the species- boundaries and the search for important taxonom- ic characters difficult. Fortunately, southern Cen- tral America has relatively few species as com- pared to Mexico or South America. As in many other genera, the weedy species are often poorly represented in herbaria. These plants often resem- ble species of Urticaceae.
Acalypha is recognized by its often long narrow spiciform, usually unisexual, inflorescences, very small $ flowers with minute anthers, 9 flowers with much-divided and slender-laciniate style branches often red or purple, broad floral bracts enlarging to enclose the fruits (in most species) and small three-seeded capsules. The <5 inflorescences are al- ways axillary. Specimens lacking mature 2 flowers and fruits may be very difficult to identify.
Key to the Species of Acalypha in Costa Rica
la. Plants of gardens and hedgerows, with brightly colored leaves or inflorescences 2
Ib. Plants of natural and disturbed vegetation, not grown for the colorful leaves or inflorescences 3 2a. Plants with conspicuous reddish pendant inflorescences, $ inflorescences usually absent; leaves
usually green A. hispida
2b. Plants with inconspicuous $ and 2 inflorescences often present on the same plant; leaves
usually red to purple A. amentacea ssp. wilkesiana
3a. 2 flowers and fruits pedicellate along the major inflorescence axes, bracts of 2 flowers remaining small and obscure; leaves > 1 2 cm long and palmately veined; species of evergreen areas below
800 m elevation 4
3b. 2 flowers and fruits sessile (solitary 2 flowers sometimes borne on long axillary pedicels in A. arvensis and A. leptopodd), bracts of 2 flowers enlarging and enveloping the fruits but sometimes difficult to see because of the pubescence (only enlarging slightly in A. radinostachyd); leaves larger or smaller, venation palmate or pinnate; species of evergreen and deciduous areas from sea level
to 2200 m elevation 5
4a. Plants usually with 2 flowers in large terminal many-branched narrowly pyramidal panicles; seeds 1.5-1.7 mm long; leaf blades becoming narrower in the lower Vj-'A, rarely ovate,
venation pinnate A. costaricensis
4b. Plants with the 2 flowers usually on slender axillary unbranched racemes; seeds 0.8-1.4 mm
46
FIELDIANA: BOTANY
long; leaf blades nearly always broadest in the lowest '/3 and ovate, venation palmate or
subpalmate A. villosa
5a. Leaves with pinnate venation, shrubs or small treelets 6
5b. Leaves with palmate or subpalmate venation (the basal pair of 2° veins prominent and terminating
at or above the middle of the blade), herbs, shrubs, or small treelets 8
6a. Leaf blades narrowed to an obtuse or acute base, only rarely slightly rounded at the petiole; 9 bracts becoming 2-4 mm long with small (< 1 mm) lobes or unlobed in fruit; seeds 1.4-
1.6 mm long [9 flowers few, axillary or at base of <3 spikes] A. diversifolia
6b. Leaf blades narrowed to the base and slightly rounded or auriculate at the petiole; 9 bracts
becoming 10-13 mm long with teeth 1-6 mm long in fruit; seeds 2.1-2.6 mm long ... 7
7a. Female flowers many in long (to 1 8 cm) conspicuous terminal inflorescences; <3 inflorescences
few A. ferdinandii
7b. Female flowers 1-few, in axils of distal leaves; $ inflorescences many A. apodanthes
8a. (from 5b) Plants shrubs or trees, > 1 m tall; 9 bracts with lobes becoming up to 2 mm long; glands
often present at the apex of the petiole 9
8b. Plants herbaceous, usually < 1 m tall; <5 bracts with lobes often 3-7 mm long (except/!, mexicand);
glands rarely present at the apex of the petioles 13
9a. Fruiting inflorescence a slender (0.2 mm thick) pendulous rachis with usually only a single terminal bract, to 4 cm long (axillary 9 flowers may also be present) [stipules 4-15 mm long
with a long-awned tip] A. leptopoda
9b. Fruiting inflorescences with rachis 0.5-2.5 mm thick, with many bracts and fruits along the
rachis, to 30 cm long 10
1 Oa. Bracts of the 9 inflorescence 2-3 mm long and not enlarging in fruit; stipule scars becoming thickened, hard and pale colored, 2-3 mm wide [stipules to 7 mm long with a narrowed terminal portion; 9 inflorescences terminal and solitary; plants of the Caribbean slope, 100-
300 m] A. radinostachya
1 Ob. Bracts of the 9 inflorescences enlarging (to 6 mm long) in fruit; stipule scars not as above
11
1 la. Stipules ovate to narrowly lanceolate, without a slender terminal awn; petioles 2-26 cm long; fruiting inflorescences axillary, to 35 cm long, pendant (see also A. obtusifolia); common and
widespread A. macrostachya
1 Ib. Stipules narrowed above the base into a long slender (0.3 mm) awn; petioles 2-13 cm long;
fruiting inflorescences terminal, to 1 8 cm long, erect; rarely collected species 12
1 2a. Leaf blades ovate, petioles to 7 cm long; margins of fruiting bracts with prominent teeth, without gland-tipped hairs; semideciduous forests at 100-800 m elevation . . .
A. schiedeana
1 2b. Leaf blades elliptic, petioles to 1 3 cm long; margins of fruiting bracts entire and with
gland-tipped hairs to 1.5 mm long; evergreen forest at 1 100 m
A. sp. aff. A. mortoniana
1 3a. (from 8b) Large-bracted 9 inflorescences present at nearly all nodes, usually short and subsessile (rarely to 4 cm long), bracts ca. 4 mm long with short (0.5 mm) rounded lobes [rarely collected,
900-2200 m elevation] A. mexicana
13b. Large-bracted 9 inflorescences only at the distal nodes; 9 bracts with lobes 1-6 mm long 14
14a. Fruiting inflorescences 10-15 mm wide, open or densely flowered and resembling the hairy spikes of a foxtail grass (Setaria spp.) [9 bracts with linear lobes 3-6 mm long, glabrous or with thin
straight hairs 1-2 mm long] 15
14b. Fruiting inflorescences 5-12 mm wide, not resembling the hairy inflorescences of a foxtail grass
17
1 5a. Flowering and fruiting 9 spikes with bracts not closely congested, bracts glabrous to very minutely puberulent or with few glandular hairs; larger leaf blades > 8 cm long; seeds > 2
mm long [uncommon in Costa Rica] A. polystachya
1 5b. Flowering and fruiting 9 spikes with bracts closely congested, bracts with thin straight hairs
to 2 mm long; leaf blades to 8 cm long; seeds < 1 .5 mm long 16
1 6a. Plants lacking gland-tipped hairs on stems but gland-tipped hair often present in the inflo-
BURGER & HUFT: FLORA COSTARICENSIS 47
rescence; stipules to 5 mm long; 2 inflorescences axillary on peduncles to 32 mm long; styles with 3-5 branches and bright red (absent in later fruiting stages); seeds 1.1-1.4 mm long;
common in Costa Rica A. arvensis
16b. Plants usually with gland-tipped hairs on stems, petioles and/or inflorescences; stipules to 2.5 mm long; 9 inflorescences consistently terminal on peduncles to 10 mm long, styles
unbranched and difficult to see; seeds 1-1.1 mm long; uncommon in Costa Rica
A. alopecuroides
17a. 2 flowers few and axillary or lacking, distal 5 flower often on a slender (0.2 mm) rachis 0.5-3 cm long; stipules often terminating in a slender transparent sharp-pointed hair; immature plants of
A. arvensis
17b. 9 flowers on spicate inflorescences, distal 2 flower not borne on a slender filament-like rachis;
stipules not terminating in a long, sharp slender hair 18
18a. Stems and leaves with many thin straight hairs 1-2 mm long; <? spikes 5-12 cm long, with thin
peduncles 1-5 cm long [rarely collected in Central America] A. triloba
18b. Stems and leaves with short (0.1-0.4 mm) hairs; $ spikes 0.8-3 cm long, with peduncles < 5 mm
long 19
19a. Fruiting bracts with rounded or triangular lobes 1-2 mm long, with hairs ca. 1 mm long; stipules
triangular to subulate; 1 100-1900 m elevation A. septemloba
19b. Fruiting bracts with linear lobes to 6 mm long, glabrous or with minute hairs; stipules linear; 10- 1000 m elevation . . .A. setosa
Acalypha alopecuroides Jacq., Collect. 3: 196. 1790. Icon. PI. Rar. 3: 19, t. 620. 1792. Figure 11.
Herbs 20-90 cm tall, bisexual (monoecious), leafy stems 0.6-3 mm thick, densely pubescent with thin straight hairs 0.2-1 mm long, also often with gland-tipped hairs 0.6-1.2 mm long; stipules 1-2.5 mm long, 0.3-0.6 mm broad at the base, subulate-linear, sparsely puberulent, persisting. Leaves with petioles 4-65(-80) mm long, 0.2- 0.5 mm thick, sparsely pubescent with thin hairs, gland- tipped hairs usually present distally, small (0.3 m) dig- itate glands sometimes present at the apex; leaf blades 1.8-8 cm long, 1.3-5.5 cm wide, ovate to ovate- trian- gular, tapering to a short-acuminate apex, margins with 14-28 teeth/side, base rounded and truncate (rarely sub- cordate), drying membranaceous, pubescent above with scattered thin straight hairs 0.2-2 mm long, with shorter hairs along the veins beneath, venation palmate, 2° veins 2-3/side of the midvein. Male inflorescences 8-30 mm long, peduncles 2-6 mm long, 0. 1-0.2 mm thick, slender and spiciform, gland-tipped hairs usually present, bracts ca. 0.4 mm long, usually obscure; $ flower buds ca. 0.4 mm diam., glabrous, perianth 0.5 mm wide at anthesis. Female inflorescences terminal, 1.5-6 cm long, flowering portion becoming 8-15 mm wide and ellipsoid to cylin- drical, peduncles 2-10 mm long, ca. 1 mm thick, bracts with linear teeth 5-8 mm long, with straight thin hairs to 2 mm long, gland-tipped hairs often present, some- times with a slender distal rachis and solitary $ flower; 2 flowers 1 /bract, sessile, hispidulous and often with gland- tipped hairs, styles 2-7 mm long, unbranched and in- conspicuous. Fruits 1.2-1.5 mm diam., subtended and enclosed by bracts to 12 mm long with a broad united (4 mm) base and linear lobes 5-8 mm long; seeds 1-1.1 mm long, 0.6-0.7 mm diam., grayish, ovoid-ellipsoid, caruncle slightly elevated, ca. 0.4 mm long, whitish.
Weedy plants of open sites in evergreen and seasonally dry habitats in the Pacific lowlands, 0- 300 m elevation (to 1400 m in Guatemala). Flow- ering and fruiting in July-August. While this spe- cies can be locally common, collections from southern Central America are few; it has not been collected in the Caribbean lowlands or in the ev- ergreen areas of the Pacific lowlands of Costa Rica. This species ranges from the southern United States and the Bahamas to Venezuela and Peru.
Acalypha alopecuroides is recognized by its small weedy habit, presence of gland-tipped hairs, short slender axillary $ spikes, bracts with long-linear teeth, thick terminal catkin-like 2 spikes, and un- divided styles. This species is very similar to A. arvensis, and the two are very closely related. Nev- ertheless, the two seem to differ quite consistently by the characters used in the key. This species has been called chimbombo in Costa Rica (Orozco 221 F).
Acalypha amentacea Roxb., Fl. Ind. ed. 1832, 3: 676. 1832, subspecies wilkesiana (Mull. Arg.) Fosberg, Smithsonian Contr. Hot. 45: 10. 1980. A. wilkesiana Mull. Arg. in DC., Prodr. 15 (2): 817. 1866.
Ornamental shrubs 2-5 m tall, monoecious, leafy stems 1.5-6 mm thick, sparsely to densely pubescent with mi- nute (0.2 mm) appressed or curved hairs; stipules 10- 25 mm long, ca. 2 mm wide at the base, narrowly lan- ceolate. Leaves with petioles 1 .2-9 cm long, 0.8-2.5 mm
48
FIELDIANA: BOTANY
thick, sparsely to densely puberulent; leaf blades 9-28 cm long, 4-18 cm wide, ovate to ovate-elliptic, apex acuminate, margin with rounded teeth 22-60/side, base obtuse to rounded and subcordate, drying chartaceous, with few short hairs along the veins above, glabrescent below, venation palmate, 2° veins 5-8/side of the mid- vein. Inflorescences mostly axillary, $ inflorescences to 25 cm long, 2 inflorescences 4-14 cm long, bracts sub- tending 2 flowers 1-4 mm long, with 1 central lobe and smaller lateral lobes; style branches to 6 mm long.
Acalypha amentacea ssp. wilkesiana is a very common ornamental shrub with foliage varying from bronze-green to reddish purple or dark red and marked with white or pink. Originally from the western Pacific, the species is now widely planted in gardens of the tropics and subtropics. It is grown at low and middle elevations (0-1500 m) in Central America. Common names are capa del rey, manto de Jesus, pastor, "beefsteak plant," "copper leaf," and "Jacob's coat."
Acalypha apodanthes Standl. & L. O. Williams, Ceiba 1 : 24 1 . 1 95 1 . A.ferdinandii var. pubescens K. Hoffm., Pflanzenreich 4. 147. 16: 64. 1924. Figure 14.
Shrubs or small treelets 1.5-3(-6) m tall, mostly mo- noecious, bark rough brown, leafy stems 1.2-3.5 mm thick, densely pubescent with straight or curved hairs 0.2-0.6 mm long; stipules 3-8 mm long, 0.5-1 mm broad at the base, narrowed ca. 1 mm above the base into a linear awn, with minute appressed hairs. Leaves with petioles 4-20(-32) mm long, 0.5-1 mm thick, usually densely hirsute with erect hairs 0.2-0.4 mm long, flat or disk-like glands sometimes present at the apex; leaf blades 5-17 cm long, 1.5-5 cm wide, narrowly elliptic to narrowly elliptic-oblong, oblanceolate or elliptic, ta- pering gradually to an acuminate apex, margins with 20- 30 teeth/side ca. 0.5 mm long, tapering gradually to the base and rounded (2-3 mm) at the petiole (subauricu- late), sparsely pubescent above with hairs ca. 0.5 mm long, more densely pubescent beneath with hairs 0.2- 0.4 mm long, 2° veins 7-12/side. Male inflorescences 2- 16 cm long, 1.5-2 mm diam., peduncles 4-10 mm long, 0.3-0.5 mm thick, densely pubescent, flower clusters ca. 1.4 mm wide, usually closely approximate, rachis 0.2- 0.4 mm thick, bracts ca. 0.6 mm long, acute; $ flowers minute, buds ca. 0.4 mm diam., pedicels to 0.7 mm long. Female inflorescences axillary to distal leaves, usually only 1 bract/node with 1 2 flower, sometimes at the base of a 3 spike, bracts 1-5 mm long and becoming 5-8 mm long in fruit, with 7-1 1 prominent linear or triangular teeth 3-6 mm long, flowers sessile; 2 flowers with ovary ca. 1.3 mm long, densely covered with straight erect hairs, style branches to 6 mm long, separate to base, white to red. Fruits enclosed within the cupulate-con- duplicate bracts, united base of bracts ca. 3 mm long; seeds 2.1-2.2 mm long, 1.6-1.7 mm diam., oblong- rounded.
Plants of evergreen forest formations of the Ca- ribbean slope and adjacent areas, 100-1400 m el- evation. Flowering in late January-September. The species is only known from central and northern Costa Rica (but see below).
Acalypha apodanthes is recognized by its soli- tary 9 bracts in distal leaf axils, long slender 6 spikes, small narrow pinnately veined leaves with small basal lobes (subauriculate), and larger seeds. This species may prove to be an unusual mor- photype of A.ferdinandii (q.v.), lacking the char- acteristic terminal 2 spikes of A. ferdinandii and usually with smaller leaves. The shared habitat (in part) and the similar phenology also suggest that these plants may be conspecific.
Acalypha arvensis Poeppig in Poeppig & Endl., Nov. gen. sp. pi. 3: 21. 1841. Figure 11.
Herbs 20-70 cm tall, older plants often with multiple branches from a woody base, leafy stems 0.9-4 mm thick, with thin whitish hairs 0.2-0.7(-1.5) mm long, smaller hairs often recurved; stipules 2-5 mm long, 0.5 mm wide at the base, narrowly lanceolate to subulate, often ter- minated by a thin transparent sharp-tipped hair. Leaves with petioles 1-3 cm long, 0.3-0.9 mm thick, sparsely to densely pubescent, lacking glands at the apex; leaf blades 1.8-7 cm long, 1.2-4 cm wide, ovate to ovate- elliptic, tapering to an acute or short-acuminate apex, margin with 1 1-23 teeth/side, cuneate to rounded and truncate at the base, drying thin-chartaceous, pubescent on both surfaces with thin straight hairs 0.2-1.9 mm long, venation palmate, 2° veins 2-4/side along the mid- vein. Male inflorescences 3-5 cm long, ca. 1 .5 mm thick, peduncles 3-25 mm long, 0.2-0.3 mm thick, puberulent; $ flowers pedicellate, perianth 0.4-0.5 mm broad at an- thesis. Female inflorescences axillary, at first 4-7 mm long with subglobose flowering portion but expanding and 24-80 mm long in fruit, becoming a dense loosely cylindrical spike 6-22 mm wide, sometimes with a distal filiform rachis with several <5 flowers or 1-3 2 flowers, peduncles 6-32 mm long, 0.4-1 mm thick, with thin whitish hairs ca. 1 mm long (gland-tipped hairs present or absent), bracts becoming 4-8 mm long with 3-7 lobes, lobes triangular at base and with linear tips 3-5 mm long; 2 flowers soon becoming enclosed within the con- gested bracts, ovary ca. 0.7 mm long, hispidulous, style branches 2-5 mm long, red. Fruits deeply 3-lobed, his- pidulous, hidden within the expanded and persistent bracts of the cylindrical infructescence; seeds 1.1-1.4 mm long, 0.7-1 mm diam., oblong-subglobose, surface grayish and minutely reticulate (x 10), caruncle ca. 0.4 mm long and slightly elevated, whitish.
Common weedy plants of open or partly shaded sites in evergreen and deciduous forest formations; 1-700 m elevation (ca. 1 100 m near San Vito and in Chiriqui). Probably flowering primarily in the wet season; fruiting mostly in July-November in
BURGER & HUFT: FLORA COSTARICENSIS
49
Costa Rica. The species ranges from Mexico to Brazil and Bolivia.
Acalypha arvensis is recognized by its herba- ceous habit, short-awned stipules, and the short thick catkin-like infructescences. The infructes- cences have a soft texture because of the thin hairs and long linear lobes of the many imbricated bracts; they are reminiscent ofCenchrus (Poaceae). Some plants may also produce small 2 inflorescences with one to three separate proximal 2 flowers and one to two distal flowers on a filiform rachis. The ax- illary inflorescences and lack of glandular hairs on stems help separate this species from the closely related A. alopecuroidea. Specimens with fruiting infructescences are much more common than those with flowers in anthesis.
Acalypha costaricensis (Kuntze) Knobl. ex Pax & Hoffm., Pflanzenreich 4, 147, 16: 16. 1924. Ri- cinocarpus costaricensis Kuntze, Rev. gen. pi. 2: 615. 1891. Figure 15.
Herbs or subshrubs 0.6-2(-4) m tall, monoecious or dioecious, leafy stems 1.2-4.3 mm thick, with thin or curved hairs 0.4-1 mm long, terete; stipules 2.5-8 mm long, 1-1.3 mm wide at the base, lanceolate to linear, glabrous or pubescent. Leaves with petioles 1.5-7 (-10) cm long, 0.5-1 .8 mm thick, pubescent or rarely glabrous, often with minute (0.5 mm) disk-like or ridged glands at the blade; leaf blades 10-22 cm long, 4.5-1 1 cm wide, elliptic to elliptic-oblong or ovate-elliptic, apex acumi- nate with narrowed tip 8-15 mm long, margin crenate- dentate with short (0.5-3 mm) teeth 1 2-28/side, rounded at the truncated base or subcordate at the petiole, drying thin-chartaceous and green, with few hairs ca. 0.6 mm long above, more densely pubescent beneath with hairs ca. 0.3 mm long, venation pinnate, 2° veins 5-10/side. Male inflorescences 5-30 cm long, 1.5-3.5 mm wide, peduncles 8-12 mm long, 0.3-0.4 mm thick, flower clus- ters closely crowded or to 1.5 mm apart, 6 flower buds ca. 0.8 mm diam. Female inflorescences terminal, 15- 40 cm long, 4-12 cm wide, paniculate and narrowly pyramidal, peduncles to 1 1 cm long and 3 mm thick, minutely pubescent, lateral branches 2-9 cm long (be- coming shorter distally), 0.2-0.4 mm thick, subtended by bracts ca. 1 mm long; flowers usually 1 /bract, sub- tended by imbricate bracts ca. 0.5 mm long, pedicels 1- 5 mm long, ca. 0.2 mm thick, puberulent; $ flowers pur- ple or dark red, sepals ca. 1 mm long, linear, ovary 1- 2.3 mm long, 1 .5 mm diam., verrucose hispidulous, style column 0.5-1 mm long, style branches 2-4 mm long, with many filamentous parts. Fruits 3-4 mm wide, 3-lobed, with erect narrow verrucose projections 0.2-0.4 mm high; seeds 1.5-1.7 mm long, 1.4-1.5 mm diam., subglobose or ovoid, smooth, brown or gray, caruncle minute.
Plants of lowland Caribbean rain forest for- mations, 20-250(-500) m elevation. (Of the 54 Costa Rican collections seen, only 1 was collected
above 250 m elevation.) Flowering and fruiting throughout the year but collected mostly in Feb- ruary-August. The species ranges from southern Mexico to Panama.
Acalypha costaricensis is recognized by the large open terminal 2 inflorescences with conspicuous reddish purple laciniate styles. The larger long- petiolate leaves, verrucose surface of the ovary, and long narrow $ inflorescences are also distinc- tive. It is a handsome and distinctive species. Be- cause the very small bracts do not enlarge in fruit and the 2 flowers are pedicellate, this species is placed in subgenus Linostachys (as is A. villosa, q.v.). This species resembles the rarely collected Ayenia mastatalensis Cristobal & Zamora (Ster- culiaceae).
Acalypha diversifolia Jacq., Hort. Schoenbr. 2: 63, t. 244. 1792. A. leptostachya H.B.K., Nov. gen. sp. 2: 96. 1 8 1 7. A. panamensis Klotzsch in Seem., Bot. voy. Herald 101. 1853. A. tabascensis Lun- dell, Lloydia 4: 51. 1941. Figure 14.
Shrubs or small trees, 1.5-5(-15) m tall, monoecious, with many arching branches, leafy stems 1-4 mm thick, sparsely to densely hirsutulous with thin hairs 0.2-0.5 mm long, glabrate, gray to dark brown; stipules 3-6(-8) mm long, 0.5-1 mm broad at the base, narrowed 1-2 mm above the base to the linear tip, minutely puberu- lent, often with a thickened convex base. Leaves with petioles 4-1 7(-30) mm long, 0.7-1.5 mm thick, sparsely to densely pubescent, glabrescent, distal glands absent; leaf blades 6-20 cm long, 2-8 cm wide, narrowly elliptic to ovate-elliptic or oblong-lanceolate, apex short- to long- acuminate, tip to 25 mm long, margins with 20-40 teeth/ side, 0-0.6 mm high, base obtuse to cuneate and often slightly rounded at the petiole, drying chartaceous, upper surfaces sparsely pubescent to glabrescent, lower surface usually pubescent along the veins with hairs 0. 1-0.6 mm long, 2° veins 4-8/side. Inflorescences axillary, spicate, mostly 3 and 2-10 cm long (sometimes on short leafless shoots forming a panicle of spikes), peduncles 0—4 mm long, 0.4-0.7 mm thick, sparsely to densely puberulent, 9 bracts 1-3 and axillary or 1-3 near the base of bisexual spikes, distal 6 portion of the spike 2-5 mm wide. Male flowers in congested or separated clusters, bracts 0.5-1 mm long, triangular, pedicels 0.6-1 mm long, buds ca. 0.5 mm diam., calyx 0.8-1 mm wide, cupulate; stamen cluster 0.5 mm wide distally, anthers ca. 0.1 mm long. Female flowers 1-3/bract, subtending bracts 1-1.5 mm long but hidden by pubescence, enlarging in fruit; ovary 0.9-1.5 mm long, ovoid and covered with short erect hairs, base of styles 1-1.5 mm long with laciniate branch- es to 4 mm long. Fruits 2x3 mm, muricate with scat- tered short (0. 1 mm) hairs, subtended by bracts 2-4 mm long, 3-4 mm broad, broadly ovate, lobes small or ab- sent, subglabrous; seeds 1.4-1.6 mm long, ca. 1.2 mm diam., oblong-rounded, dark brown, smooth.
Common plants of evergreen formations and shaded sites in deciduous forest formations (often
50
FIELDIANA: BOTANY
found along riverbanks), 20-1100 m elevation. Flowering in December-August (primarily Feb- ruary-May); fruiting in March-July. This species ranges from Mexico to Peru.
Acalypha diversifolia is recognized by the pin- nately veined leaves lacking glands at the petiole/ blade juncture, dense <5 flowers often forming thick (4-5 mm) spikes, few 9 flowers in leaf axils or at base of rare bisexual spikes, and few fruit sub- tended by subglabrous bracts lacking well-devel- oped teeth. The paucity of 9 flowers and rarity of fruit among the many collections of this common Central American species is unusual. This may be due to the late development of the difficult-to-see axillary fruits. The species has been called "costilla de caballo" and "costilla de danto" in Honduras.
Acalypha ferdinandii K. Hoffm., Pflanzenreich 4, 147. 16: 63. 1924. Figure 14.
Shrubs or subshrubs 0.7-3(-6) m tall, usually monoe- cious, leafy stems 0.7-4 mm thick, with short (0.5 mm) hairs or glabrous; stipules 3-11 mm long, ca. 1 mm wide at the base, contracted 1-2 mm above the base into a linear awn, glabrous or with thin appressed hairs 0.1- 0.2 mm long. Leaves with petioles 4-34(-60) mm long, 0.6-1.5 mm thick, glabrous or with few short hairs in early stages (rarely densely pubescent), small glands or pits sometimes present at the apex; leaf blades 6-22 cm long, 2-9 cm wide, narrowly elliptic-obovate to oblan- ceolate or elliptic, usually broadest at or above the mid- dle, tapering gradually to the acuminate apex, serrations 1 1-35/side, 0.3-1 mm high, blade narrowed below the middle, rounded at the petiole and often auriculate with small (0-2 mm) basal lobes, drying chartaceous, gla- brescent above, glabrous or with thin short (0.3-0.7 mm) hairs beneath, 2° veins 7-10/side. Male inflorescences axillary to distal leaves, 4-1 2 cm long, ca. 3^1 mm diam., yellow-green, peduncles 3-15 mm long, ca. 0.5 mm diam. and glabrous or pubescent, flower clusters closely con- gested; 6 flowers 0.6-1 mm wide, borne on pedicels 0.5- 1 mm long, anthers ca. 0.1 mm long. Female inflores- cences terminal or near- terminal, 6-18 cm long and spi- cate, 10-15 mm diam. (including style branches), red- dish, bracts 5-8 mm long, subtending 1-3 sessile 9 flow- ers, enlarging in fruit, teeth of the bracts 0.5-3 mm long, acute; 9 flowers with ovary ca. 1 mm long, ovoid and covered with erect-ascending hairs, style branches many, laciniate-filamentous, 2-6 mm long, white to red or pink. Fruits 2x3 mm, strongly 3-lobed, enclosed within the enlarged (10 x 13 mm) conduplicate bracts with 5-1 1 teeth 1-5 mm long and triangular to linear; seeds 2.4- 2.6 mm long, 1.4—1.6 mm diam., oblong, surface smooth.
Plants of evergreen and partly deciduous forest formations, 20-1300 m elevation (rarely collected below 500 m on the Caribbean slope in Costa Rica). Probably flowering throughout the year; fruiting in January-July. The species ranges from Guatemala to central Costa Rica.
Acalypha ferdinandii is recognized by the long thick terminal 2 spikes with conspicuous toothed bracts and the usually narrowly obovate leaves with pinnate venation that taper to a rounded small-auriculate base. This species is quite similar to A. apodanthes (q.v.) with smaller leaves and solitary 9 flowers, and it is possible that the two are conspecific.
Acalypha hispida Burm., Fl. Ind. 203, pi. 61, f. 1. 1768.
Ornamental shrubs 1.5-3 m tall, dioecious, leafy stems minutely hirsutulous with hairs ca. 0.3 mm long. Leaves with petioles 2-5 cm long, ca. 1.5 mm thick, hirsutulous; leaf blades 9-18 cm long, 5-11 cm wide, ovate, apex usually short-acuminate, margin with 15-30 teeth/side ca. 1 mm high, base rounded, drying thin-chartaceous, glabrescent above, minutely puberulent on the veins be- neath, venation palmate, 2° veins 3-5/side on the mid- vein. Inflorescences 9 in cultivated material, 15-35 cm long, 6-25 mm wide, pendulous, densely flowered and reddish from the many style branches; 9 flowers with ovary 1 x 2 mm, densely covered with minute erect hairs, style branches 5-7 mm long; fruits and seeds usu- ally not developing.
Acalypha hispida is planted as an ornamental shrub because of its colorful pendant red or red- dish purple spikes. Originally from Malaysia, it is now grown throughout the tropics and subtropics. In Central America it is grown at low and middle elevations (0-2000 m). Common names are cola degato, coladezorro, rabodegato, "chenille plant," "red-hot cattail," and "red cattail."
Acalypha leptopoda Mull. Arg., Linnaea 34: 39. 1865. A. lotsii J. D. Smith, Hot. Gaz. 20: 544. 1895. Figure 15.
Shrubs or small treelets, monoecious, 1-3 m tall, often clambering or leaning over others, leafy stems 0.6-4 mm thick, sparsely to densely pubescent with hairs 0.1-0.5 mm long, usually glabrescent and dark reddish brown; stipules 3-15 mm long, ca. 1 mm broad at the base, narrowed 1-2 mm above the base into a linear awn, persisting. Leaves with petioles 3-60(-70) mm long, 0.2- 1 .3 mm thick, sparsely to densely pubescent, with minute (0.3 mm) fimbriate glands at the adaxial apex; leaf blades 2_12(-16) cm long, l-6(-9) cm wide, ovate to ovate- triangular or ovate-elliptic, tapering gradually to the acu- minate apex, margins with 22-38 serrations/side ca. 1 mm high, base broadly obtuse or rounded and subcor- date, drying thinly chartaceous, sparsely pubescent above, more densely pubescent beneath, venation palmate, 2° veins 4-7/side of the mid vein, strongly ascending. Male inflorescences 2-11 cm long, 1.5-2 mm thick, peduncles 3-16 mm long, ca. 0.3 mm thick, sparsely to densely pubescent, bracts ca. 1 mm long, pedicels 0.4-0.8 mm long; $ flower bud ca. 0.4 mm diam., broadly ovoid,
BURGER & HUFT: FLORA COSTARICENSIS
51
perianth ca. 0.7 mm broad at anthesis. Female inflores- cences axillary, pendant on filiform (0.1-0.2 mm) pe- duncles 1 1-38 mm long, usually with 1 terminal bract (rarely 2-3), bracts 1.5-3 mm long, subtending 1-3 ses- sile flowers; 9 flowers ca. 2 mm long in early stages, ovary 0.7-1 mm long, hispidulous, styles 3-5 mm long. Fruits verruculose, subtended by bracts 4-7 mm wide with 7- 1 1 triangular and acute or acuminate teeth 1-3 mm long; seeds 1.6-1.9 mm long, 1.2-1.3 mm long, oblong-ellip- soid, smooth.
Plants of evergreen lower montane forest for- mations, (100-)500-1700 m elevation. Probably flowering throughout the year but with most col- lections made in June-January. The species ranges from southern Mexico to western Panama.
Acalypha leptopoda is recognized by the slender pendulous 2 spikes usually with only a single ter- minal bract and one to two flowers, thin ovate leaves with palmate venation and minute glands at the apex of the petiole, awned stipules, and lower montane habitats. There are sometimes more than one inflorescence per leaf axil, but these ap- pear to be borne on short-shoots. Different col- lections can vary greatly in the density of pubes- cence. This species is very similar to A. unibrac- teata Mull. Arg. of southern Mexico and northern Central America.
Acalypha macrostachya Jacq., Hort. Schoenbr. 2: 63, t. 245. 1797. A. seemannii Klotzsch in Seem., Bot. voy. Herald 102. 1853. A. pittieri Pax & K. Hoffm., Pflanzenreich 4, 147; 16: 147. 1924. A. hicksii Riley, Kew Bull. 1927: 126. 1927, ex char. A. fertilis Standl. & L. O. Williams, Ceiba 1: 146. 1950, ex char. Figure 15.
Shrubs or weak-stemmed treelets l-3(-5) m tall, mo- noecious or dioecious, leafy stems 2.5-1 1 mm thick, densely to sparsely pubescent with hairs 0.3-1 .4(-2) mm long, terete; stipules 5-16 mm long, 3-7 mm broad, ovate-lanceolate and acuminate or subulate, a slender linear tip to 10 mm long sometimes present, veins 3-5 and parallel with midrib, pubescent to glabrous. Leaves with petioles 2.5-26 cm long, 1-3.8 mm thick, sparsely to densely pubescent, small (0.5-0.8 mm) glands some- times present at the apex; leaf blades (10-) 15-24 cm long, (5.5-)8-17 cm wide, ovate to ovate-triangular, ta- pering gradually to the acute or acuminate apex, nar- rowed tip 6-18 mm long, margin with 30-60 teeth/side ca. 1 mm high, base abruptly rounded and truncated (cordate in larger leaves), drying chartaceous, with straight hairs 0.6-1 .3 mm long on the upper surface, more dense- ly pubescent beneath, venation palmate or subpalmate, 2° veins 5-1 I/side of midvein, 3° veins subparallel. Male inflorescences 4-20 cm long, peduncles 3-9 mm long, 0.6-1 .5 mm thick, flowering part 2.5-5 mm thick, bracts 0.7 mm long, flower clusters closely crowded, pedicels to 1.5 mm long; 6 flowers 0.8 mm diam. in bud, 1 mm wide at anthesis, 0.7 mm long, sepals with straight hairs
to 0.4 mm long. Female inflorescences axillary, 9-35 cm long, 5-14 mm wide (including styles), peduncles 1-10 mm long, 1-1.9 mm thick, usually densely pubescent, flowers 1 /bract, up to 6 mm distant along the rachis bracts ca. 1 mm long at anthesis and covered with whit- ish hairs, enlarging in fruit, with 5-12 major veins and teeth ca. 1 mm long; 9 flowers with ovary 1-1.5 mm long, ovoid, covered with straight ascending hairs ca. 0.7 mm long, becoming enclosed within the subtending bract, style branches exserted and 1.5-8 mm long, filiform- laciniate and reddish. Fruits 3-5 mm wide, sessile and enclosed within the enlarged (8x8 mm) cupulate-con- duplicate bracts; seeds 1.9-2.2 mm long, 1.4-1.8 mm diam., ovoid-globose, smooth, dark brown, caruncle a whitish area ca. 0.5 mm long.
Plants often found in second growth of ever- green wet forest and partly deciduous forest for- mations on both the Caribbean and Pacific slopes, 10-1200 m elevation. Flowering throughout the year (mostly January-May); fruiting February- May. This species ranges from southern Mexico to Bolivia and Brazil; it may be present on Cocos Island (see below).
Acalypha macrostachya is recognized by the generally larger leaves, long pendant inflores- cences, the enlarged fan-like floral bracts (not pres- ent at anthesis), and larger seeds. Most plants ap- pear to be monoecious with several spikes of one sex followed by several spikes of the other sex in more distal leaf axils. Rarely, 2 spikes may have $ flowers near the apex. The pubescence is grayish white in life but pale yellowish in herbarium ma- terial. Different collections can vary greatly, from sparsely puberulent to densely villous. The sepa- ration of such a variable species into varieties based on pubescence serves no useful purpose (cf. Stan- dley & Steyermark, 1949, p. 39). Two type col- lections from Cocos Island may prove to be this species: Pittier 16246 (photo B at F), type of A. pittieri, and Hicks 456 (K, not seen), type of A. hicksii. We have seen no material of this genus from Cocos Island.
Acalypha mexicana Mull. Arg., Linnaea 34: 41. 1865. A. indica L. var. mexicana (Mull. Arg.) Pax & K. Hoffm., Pflanzenreich 4, 147, 16: 35. 1924. Figure 11.
Herbs 1 5^*0 cm tall, branched at the base with erect unbranched stems, leafy stems 0.3-1.8 mm thick, with minute (0.2-0.3 mm) curved hairs along 2 longitudinal lines; stipules 0.5-2 mm long, filiform, minutely puber- ulent, deciduous. Leaves with petioles 6-45 mm long, 0.2-0.6 mm thick, pubescent with thin straight or curved hairs; leaf blades 1-5 cm long, 0.8-3 cm wide, ovate to ovate-rhombic, apex obtuse or bluntly acute, margin with 6-15 teeth/side, base rounded and obtuse to truncate,
52
FIELDIANA: BOTANY
drying membranaceous, with scattered straight hairs 0.5- 1.2 mm long on the upper surface, with shorter (0.4 m) hairs along the veins above, venation palmate, 2° veins 2-3/side of the midvein. Inflorescences axillary, 3 spikes 1-2 cm long, slender, falling early, $ to 4 cm long with 3-6 distant bracts or 1-2 bracts crowded in the leaf axils, sessile or short-pedunculate, sometimes with a filamen- tous extension of the rachis and solitary distal 2 flower. Fruits becoming 3 mm diam., subtended by an ovate to reniform bract 3-6 mm long, 5-12 mm wide, with 9-13 rounded distal lobes 0.5-1 mm long, minutely pilose or ciliolate along the margin; seeds 1-1.2 x 0.6-0.7 mm, ovoid-ellipsoid with acute apex, surface smooth, grayish.
Rarely collected weeds of open sites, at 900- 2100 m elevation in Costa Rica. More common in Mexico and Guatemala, the species is probably an introduction in Costa Rica.
Acalypha mexicana is recognized by its short erect unbranched stems, palmately veined leaves with serrate margins on slender petioles, short in- florescences at almost all nodes, and foliaceous bracts with short rounded lobes. We have seen only four Costa Rican specimens, from the Valle Central, Cartago, and the lower slopes of Volcan Irazu. This species has also been thought to be a variety of the Asian A. indica L.
Acalypha obtusifolia Pax & K. Hoffm., Pflanzen- reich4, 147, 16: 147. 1924.
Shrubs; stipules ca. 5 mm long, lanceolate. Leaves with petioles 1-3.5 cm long, slender; blades 10-12 cm long, 6-7.5 cm wide, broadly ovate, apex obtuse or short- acute, margin denticulate, base obtuse, membranaceous, glabrous or subglabrous, palmately 5-veined. Fruiting inflorescence 10-1 5 cm long, short-pedunculate, sparsely pilose, bracts 3-5 mm long, 6-7 mm wide, obovate- truncated, with 13-15 teeth, sepal triangular, styles ca. 5 mm long; seeds 2 mm long.
This species was based on a single collection from Punta Mala along the Pacific coast (Tonduz 6823, probably destroyed at B). We have not seen isotypes. It was placed close to A. macrostachya Jacq. by Pax and Hoffmann and may be an unusual small-leaved form of that species.
Acalypha polystachya Jacq., Hort. Schoenbr. 2: 64, t. 246. 1797.
Herbs 35-90 cm tall, leafy stems 0.7-8 mm thick, sparsely puberulent with curved hairs 0. 1-0.3 mm long, glabrescent and terete; stipules 0.3-1 mm long or absent, linear, caducous. Leaves with petioles l-9(-15) cm long, 0.4-1.7 mm thick, glabrous or sparsely puberulent with curved hairs to 0.4 mm long; leaf blades 4-1 1(- 16) cm long, 2.5-7.5(-12) cm wide, ovate to ovate-elliptic, apex short-acuminate, rounded to the obtuse or truncate base,
teeth 20-38/side, drying membranaceous, with scattered thin straight hairs to 1 .4 mm long on the upper surface, glabrous to sparsely pubescent beneath, venation pal- mate, 2° veins 2-6/side on the midvein. Male inflores- cences 9-60 mm long, peduncles 5-20 mm long, 0.2- 0.3 mm thick, flowering portion ca. 2 mm wide, pedicels to 0.8 mm long; <5 flower buds ca. 0.5 mm diam. Female inflorescences terminal or in distal axils, 10-30 mm long and 2-3 mm thick in early stages, becoming 4-12 cm long and 1-2 cm thick in fruit, bracts usually subtending
2 sessile flowers, bracts with 7-12 narrow lobes elon- gating in fruit; 9 flowers with ovary ca. 0.5 mm long and styles 2 mm long in early anthesis. Fruits 2.4 mm broad, 2-3 mm long, with smooth rounded surfaces, subtended by bracts developing elongated linear teeth to 1 1 mm long; seeds 2.4-2.7 mm long, 1.9-2.1 mm diam., ovoid with an acute tip (beak), surface prominently rugose.
Uncommon weedy plants of open sites in both deciduous and evergreen vegetation, 1—400 m el- evation. Flowering and fruiting primarily in June- August. The few Costa Rican collections seen come from the Pacific lowlands. The species ranges from Mexico to Ecuador.
Acalypha polystachya is recognized by the her- baceous habit, palmate leaves with few hairs, short slender $ spikes, 9 spikes becoming thick with ex- panded glabrous linear-toothed bracts, and large fruit with somewhat rugose surface. The very small stipules are quite unusual.
Acalypha radinostachya J. D. Smith, Hot. Gaz. 54:
243. 1912.
Shrubs, subshrubs or small treelets, 1-3 m tall, leafy stems 2-6 mm thick, minutely (ca. 0.2 mm) appressed- puberulent; stipules 6-13 mm long, lanceolate or subu- late with a long narrow apex, caducous with the base becoming thickened and pale colored, ca. 2 mm wide. Leaves with petioles 2-23 cm long, 1-2.5 mm thick, appressed puberulent or subglabrous, with sessile glands 0.5-1 mm wide at apex adaxially; leaf blades 1 1-26 cm long, 6-15 cm wide, ovate to ovate-elliptic, apex acu- minate, margin strongly serrate with 1-3 teeth/cm, base narrowed and rounded, subcordate to truncate, drying thinly chartaceous and dark green, subglabrous or mi- nutely puberulent beneath at maturity, venation pal- mate, 2° veins 3-5/side of the midvein. Male inflores- cences axillary to distal leaves, solitary, 8-22 cm long, spicate, peduncles ca. 1.3 mm thick, flowering portion ca. 2 mm thick, minutely puberulent, bracts 0.5 mm long, difficult to see, glomerules with 3-6 flowers; <5 flower buds ca. 0.4 mm diam., globose. Female inflorescences terminal, solitary, 23—45 cm long, spicate, peduncles 2- 2.5 mm thick, densely or sparsely puberulent, bracts 2-
3 mm long, becoming 4 mm wide, with 2-3 lobes 0.5- 1 .2 mm high, green but drying dark, bracts closely clus- tered or separate; 2 flower 1 /bract, ovary ca. 2 mm long, 2-3 mm wide, broadly ovoid, glabrous, styles 3-6 mm long, laciniate. Fruits ca. 2-2.5 mm long, ca. 3 mm wide, sessile, subtended by bracts not exceeding 3 mm in length, to 5 mm wide.
BURGER & HUFT: FLORA COSTARICENSIS
53
Plants of the wet evergreen Caribbean slope, 100-300 m elevation. Flowering February and May-September. The species is known only from La Selva and the Llanuras de Santa Clara (/. D. Smith 6849 us the type) in north-central Costa Rica.
Acalypha radinostachya is recognized by its long terminal (apparently erect) 2 inflorescences, 2 bracts that do not become significantly enlarged, larger ovate leaves with large blunt teeth, and the thick hard whitish base where the stipules were at- tached. The 2 inflorescences are described as green, with style branches sometimes becoming white. Acalypha macrostachya is vegetatively similar but the blades are broadly rounded at the base, and the stipule scars do not become hard and smooth. Also, A. radinostachya is never densely villose as are some collections of A. macrostachya.
Acalypha schiedeana Schldl . . Linnaea 7: 304. 1 832. Figure 14.
Shrubs 1-3 m tall, much branched, leafy stems, 1.3- 5 mm thick, glabrous or with thin whitish hairs 0.2-0.4 mm long; stipules 7-10 mm long, 0.7-1.2 mm broad at the base, filiform (ca. 0.2 mm thick) above the short (ca. 1 mm) base. Leaves with petioles 2-7 cm long, 1.1-1.5 mm thick, glabrous or pubescent, usually with small (0.2 mm) digitate glands at the apex; leaf blades 6-18 cm long, 4-1 1 cm wide, ovate to elliptic-ovate, apex usually short-acuminate, margin with 12-35 teeth/side, base rounded and truncate or subcordate, drying membra- naceous, with thin hairs 0.3-0.8 mm long on veins above and below, venation palmate, 2° veins 3-4/side along the midvein. Male inflorescences 1-13 cm long, ca. 1.5 mm wide, peduncles 2-14 mm long, ca. 0.6 mm thick, pubescent, pedicels ca. 0.5 mm long; <3 flower with peri- anth ca. 0.4-0.5 mm wide, anther-clusters 0.4-0.5 mm wide. Female inflorescences terminal, 4-18 cm long, be- coming 6-1 4 mm thick in fruit, peduncles 6-14 mm long, 0.7-0.9 mm thick, pubescent, flowers at first with minute bracts and separate along the rachis, sessile, becoming congested; 9 flowers with ovary 0.5-1.5 mm long, mi- nutely hispidulous, styles 1.5-3 mm long, laciniate dis- tally. Fruits ca. 3 mm broad, smooth, solitary within conspicuous bracts 3-12 mm long, with 7-13 lobes 1-2 mm long, triangular to lanceolate, bracts usually with thin hairs 0.4-1.5 mm long; seeds 1.7-2 mm long, 1.3- 1 .5 mm diam., ovoid, grayish, caruncle not elevated, 0.7 mm long.
Uncommon plants of moist evergreen sites in deciduous forest formations on the Pacific slope, 0-800 m elevation in Costa Rica. Flowering in late May-early June; fruiting in June (June-De- cember in northern Central America). This species is known in Costa Rica from Sta. Rosa N.P., ri- parian forest near Bagaces and Canas, and San Luis (below Monteverde). The species ranges from
central Mexico to northern Puntarenas Province, Costa Rica.
Acalypha schiedeana is recognized by the shrub- by habit, ovate leaves with palmate venation, nar- row stipules, conspicuous terminal 2 spikes, and broad bracts with relatively short teeth subtending the fruit.
Acalypha septemloba Mull. Arg., Flora 55: 27. 1872. Ricinocarpus irazuensis O. Ktze., Rev. gen. pi. 2: 616. 1891. A. irazuensis (O. Ktze.) Pax & Hoftm., Pflanzenreich 85 (IV, 147, XVI): 53. 1924. Figure 14.
Herbs or subshrubs, to 1 m tall, leafy stems 0.3-2 mm thick, with thin curved whitish hairs 0.2-0.4 mm long; stipules 0.5-1.5 mm long, triangular to subulate, cadu- cous. Leaves with petioles 4—40 mm long, 0.3-0.6 mm thick, pubescent with thin whitish hairs, with minute digitate glands at the apex or adjacent to a gland-like area on the blade; leaf blades 1-7 cm long, 1-4 cm wide, ovate to ovate-triangular (suborbicular in very small leaves), apex acute or subacuminate, margin with 1 2-22 teeth/side, base rounded and obtuse or truncate, drying membranaceous, with scattered appressed straight hairs 0.2-0.9 mm above, with shorter hairs beneath, venation palmate or subpalmate, 2° veins 2-3/side on the mid- vein. Male inflorescences 0.8-2 cm long, 1.5 mm wide, bracts ca. 0.6 mm long, peduncles ca. 3 mm long, ped- icels 0.5 mm long; <3 flower buds ca. 0.4 mm diam. (the mostly <? inflorescences often bisexual with 1-2 $ flowers at apex or base). Female inflorescences terminal, 2-9 cm long and 7 mm wide, enlarging in fruit to 10 mm wide, peduncles 0—4 mm long; 2 flowers 1 /bract, sepals 0.5- 0.8 mm long, ovary ca. 0.6 mm long, style branches 2- 4 mm long, reddish. Fruits ca. 2.6 mm diam., subtended by bracts 3-5 mm long, to 6 mm wide, with short (1-2 mm) triangular or digitate lobes; seeds ca. 1.3 x 0.8 mm, ovoid-ellipsoid, smooth.
Uncommon plants of evergreen montane for- mations, 1100-1900 m elevation. Flowering in July-January; fruiting in November-December. The species ranges from central Costa Rica to western Panama.
Acalypha septemloba is recognized by its higher- elevation habitat, short weak-stemmed habit, very small stipules, glandular processes at the junction of petiole and blade, and floral bracts with short acute or rounded lobes. The reddish style branches are conspicuous at anthesis.
Acalypha setosa A. Rich, in Sagra. Hist. fis. Cuba Dot. T. XI: 204. 1850.
Herbs 0.3-0.8 m tall, usually with a single main stem and few lateral branches, leafy stems 0.8-4 mm thick, with thin curved hairs ca. 0.2 mm long; stipules 1-2 mm long, 0. 1-0.2 mm wide, persisting or deciduous. Leaves
54
FIELDIANA: BOTANY
with petioles 1-7 cm long, 0.3-0.8 mm thick, with thin curved ascending hairs; leaf blades 2.5-10 cm long, 1.5- 6.5 cm wide, broadly ovate to ovate-triangular, abruptly short-acuminate at the apex (acute), marginal teeth 5- 8/cm, base broadly obtuse to truncated, drying mem- branaceous, with straight appressed hairs 0.4-0.8 mm long on the upper surface or glabrescent, lower surface with inconspicuous hairs along the major veins, venation palmate, midvein with 2° veins 2-4/side. Male inflores- cences at distal nodes, solitary, 8-25 mm long, flowering portion 1.5-2 mm diam., rachis 0.2-0.3 mm thick, fil- aments 0.2-0.4 mm long; $ flowers ca. 0.4 mm wide at anthesis. Female inflorescences axillary to distal nodes or appearing terminal (abnormal $ inflorescences often at lower nodes), 3-12 cm long, flowering portion 3-1 1 mm wide, bracts 2-7 mm long, with 9-13 narrow lobes up to 6 mm long, enclosing 1 9 flower; ovary pubescent, styles not conspicuous. Fruits 1.5-2 mm long, 2-3 mm wide, 3-lobed, with few erect hairs; seeds 1.2-1.4 mm long, 1-1.2 mm wide, subglobose to ovoid, smooth.
Weedy plants of open or disturbed sites in de- ciduous and evergreen areas, 5-900 m elevation (in northern Central America). Flowering and fruiting throughout the year in northern Central America. The species ranges from Mexico to northern Costa Rica and from the West Indies to northern South America.
Acalypha setosa is recognized by its short her- baceous habit, broadly ovate leaves with truncated base and palmate venation, and the 9 bracts with long narrow lobes. The small linear stipules and very short 6 spikes are also characteristic. This species may be mistaken for A. polystachya, but the seeds of the two species are very different. This species has only recently been collected in Guan- acaste Province (Wilbur et al. 23031 & 31203 DUKE) and may be a recent introduction.
Acalypha triloba Mull. Arg., Linnaea 34: 23. 1 865.
Herbs to ca. 1 m tall, leafy stems 1-4 mm thick, hirsute with thin straight somewhat retrorse hairs 1-2 mm long, shorter (0.1-0.3 mm) hairs also present; stipules 1.5-5 mm long (or absent), linear to narrowly triangular. Leaves with petioles 2-7 cm long, 0.5-0.8 mm thick, with thin straight hairs 0.3-2 mm long; leaf blades 4—10 cm long, 2-6 cm wide, ovate-elliptic to ovate or ovate-triangular, apex acuminate, margin serrate with ca. 5 teeth/cm (Cos- ta Rica) or 2-3 teeth/cm (Mexico and Guatemala), base obtuse to rounded and truncate, drying chartaceous, sur- faces with thin straight hairs 0.5-1.5 mm long, venation palmate, 2° veins 4-5/side of midvein and strongly as- cending. Male inflorescences solitary, 5-12 cm long, pe- duncles 8-60 mm long, flowering portion 1.5-2.5 mm thick, flower buds 0.3-0.5 mm diam., pedicels less than 1 mm long; <5 flowers with anthers 0.2-0.3 mm wide. Female inflorescences terminal or axillary to distal leaves, solitary, 3-7 cm long, 3-12 mm wide (including styles), rachis densely pubescent, flowers 2-3/bract (original de- scription) or apparently 1 /bract (Costa Rican collection),
sessile, bracts with 3 distal lobes; $ flowers with calyx ca. 1 mm long, ovary densely pubescent, styles 4-6 mm long, laciniate, becoming reddish. Fruits and fruiting in- florescences not seen; seed foveolate-puncticulate (orig- inal description).
Acalypha triloba is a poorly known species of Mexico and Guatemala with a single Costa Rican collection placed here provisionally. The species is unusual because of its $ spikes with long thin peduncles, long slender petioles, and the stems and leaves with straight slender hairs to 2 mm long. A Guatemalan collection (Steyermark 51959 F) was collected at 2500 m elevation, but the Costa Rican collection came from a partly shaded roadside at ca. 100 m elevation near Bahia El Coco in Guan- acaste Province in late July (Burger & Burger 7753, distributed as A. polystachya?). The Costa Rican collection differs in having more finely serrate leaves and less well-developed stipules, and the 2 flowers appear to be solitary on the young spike. We thank Geoffrey Levin for the provisional de- termination of this collection.
Acalypha villosa Jacq., Enum. Syst. PI. 32, 1760; Sel. Stirp, PI. Amer. 254, t. 183, f. 61. 1763. Figure 15.
Weak-stemmed shrubs or small treelets 0.5-3(-8) m tall, usually monoecious, leafy stems 1.3-5 mm thick, sparsely to densely pubescent with minute (0. 1 mm) or villose yellowish hairs 0.3-0.9 mm long; stipules 2-10 mm long, narrowly triangular to lanceolate, acuminate, often with a distinct midvein and thin lateral margins. Leaves with petioles 2.5-14 cm long, 0.6-2 mm thick, sparsely to densely pubescent, often with elevated or lanceolate glands 0. 5- 1 . 5 mm long at the apex and drying dark; leaf blades 8-17(-25) cm long, 5-ll(-13.5) cm wide, ovate to ovate-triangular, tapering gradually to the acute or acuminate apex, margin crenate-serrate with 25-75 teeth/side 0.5-2 mm high, usually abruptly round- ed to the truncated or cordate base, drying thin-char- taceous, sparsely strigose to glabrate above, more densely pubescent below with hairs 0.3-0.9 mm long (rarely gla- brous), venation palmate or subpalmate, 2° veins 4-7/ side of the midvein, 3° veins subparallel; minute pellucid dots sometimes present on the lower surface. Inflores- cences almost always unisexual and unbranched, usually axillary, often with a series of axils bearing the same sex followed by a number of axils bearing the other sex, puberulent. Male inflorescences 4-12 cm long, 1.8-3.6 mm diam., spicate, peduncles 4-12 mm long, 0.3-1 mm thick, flower clusters sessile and closely congested, ob- scuring the rachis until after anthesis, bracts 0.7-1 mm long, broadly triangular, often ciliolate, pedicels 0.5-1.5 mm long; <5 flowers ca. 1 mm wide, sepals ca. 0.5 mm long, with a glabrous perianth-like inner whorl drying and brownish (ca. 0.4 mm long), anthers ca. 0.1 mm long. Female inflorescences becoming racemose, 5-16 cm long, peduncles 5-25 mm long, rachis 0.2-0.3 mm thick, flowers mostly solitary, subtended by minute (0.5
BURGER & HUFT: FLORA COSTARICENSIS
55
mm) bract and tufted hairs, pedicels 1-2 mm long, to 4 mm in fruit; 2 flowers with sepals ca. 0.5 mm long, persisting in fruit; ovary 0.8-1.3 mm long, style column 0.3 mm long, style branches 1-2 mm long, often drying yellowish (red in life). Fruits 1.5 x 2 mm, prominently 3-lobed, muricate with narrow projections 0.1-0.3 mm long, persisting columella ca. 0.7 mm long, expanded apically; seeds 0.8-1.4 mm long, 0.7-1.3 mm diam., ovoid or subglobose, smooth, pale brown.
Plants of evergreen forest formations on both Caribbean and Pacific coasts, 1-800 m elevation. Probably flowering and fruiting throughout the year in Central America. The species ranges from Mex- ico to Brazil and Paraguay.
Acalypha villosa is recognized by the slender 2 racemes with small isolated flowers and the base of the leaf blades consistently broad and rounded to a truncated or cordate base. Occasional collec- tions with near-terminal 2 inflorescences with many slender lateral branches occur in Honduras and Nicaragua (rarely in Costa Rica) and can be easily confused with A. costaricensis. This species is less common in Costa Rica than the closely related A. costaricensis (q.v.).
Acalypha sp. aff. A. mortoniana Lundell, Bull. Torrey Bot. Club 64: 552. 1937.
Shrubs ca. 3.5 m tall, leafy stems 1.2-4 mm thick, densely puberulent with short (0.2-0.3 mm) curved as- cending or appressed hairs; stipules 3-4 mm long, linear or setaceous. Leaves with petioles 3-13 cm long, 0.8- 1 .8 mm thick, densely minutely puberulent, apical glands
absent; leaf blades 12-18 cm long, 5-8 cm wide, elliptic to elliptic-oblong or narrowly ovate-elliptic, apex acu- minate, margin with short (0.5 mm) gland-tipped teeth, base cuneate to obtuse, drying membranaceous or thin- chartaceous, dark, minutely puberulent on the veins above, sparsely puberulent beneath, venation palmate or subpalmate, midvein with 4-5 2° veins/side. Male inflorescences 6-12 cm long, 3-4 mm thick (with flow- ers), rachis 0.2-0.3 mm thick, puberulent, bracts ca. 1 mm long, subtending 3-7 flowers, pedicels ca. 1 mm long; 3 flowers ca. 1 mm wide. Female inflorescences terminal, to 14 cm long in fruit, not seen at an thesis, fruiting bracts 5-6 mm long, broadly conduplicate-ren- iform, apically emarginate or with a short sinus, margin entire and with prominent gland-tipped hairs 0.5-1.5 mm long, surfaces with few thin hairs, each bract sub- tending a solitary fruit. Fruits 5-6 mm long, ca. 6 mm wide, subglobose, sessile, partly enclosed by the bract; seeds 3.7—4.2 mm long, ca. 3 mm diam., ovoid-ellipsoid, smooth, brown.
Known only from primary evergreen forest at Estacion Cacao (10°55'38"N,85°29'38"W) at 1100 m elevation. Flowering and fruiting in June. This taxon is represented by a single collection (Delgado 29) from northwestern Costa Rica.
Acalypha sp. aff. A. mortoniana is recognized by its larger elliptic leaves on long petioles, slender $ spikes, and prominent erect fruiting spikes with floral bracts bearing gland-tipped hairs along their rounded entire margins. Our collection is very similar to material of A. mortoniana from Gua- temala and may prove to be a southern subspecies. The following key highlights the differences be- tween our collection and the Guatemalan material.
la. Leaf blades mostly elliptic and narrowed gradually to the base, serrations small or obscure; fruiting bracts often emarginate at the apex (Delgado 29)
Ib. Leaf blades mostly ovate and rounded at the base, usually with prominent (0.5-1.5 mm high) serrations; fruiting bracts often with a single apical tooth A. mortoniana
Acidoton Swart/
Shrubs or small treelets, dioecious, stinging hairs sometimes present, spines absent; stipules paired at the leaf base, small, deciduous or persistent. Leaves alter- nate, simple, petiolate, without glands or stipels; leaf blades entire to crenate or dentate, pinnately veined, domatia often present. Inflorescences axillary, racemose with flowers in fascicles along the length of the single rachis, bracts eglandular, 6 flowers subsessile or pedi- cellate, 9 flowers pedicellate. Male flowers with 3-5 se- pals, valvate in bud, petals absent, disk absent or part of the raised receptacle; stamens ca. 22-60, filaments free, slender, glabrous, anthers dehiscing longitudinally, extrorse, connective with a minute tuft of stinging hairs at its apex; pistillode absent. Female flowers with 5-6 sepals, narrow and imbricate, petals and disk absent;
ovary 3-locular, covered with stiff stinging hairs, ovules 1/locule, styles with basal column and 3 papillate branches. Fruits capsular, deeply 3-lobed and breaking into 3 2-valved cocci, surfaces with stinging hairs; seeds rounded, ecarunculate.
A small genus of approximately six species cen- tered in the Caribbean. It is related to Tragia but differs in having the connective terminated by stinging hairs. One species is found in Central America.
Acidoton nicaraguensis (Hemsl.) G. Webster, Ann. Missouri Bot. Gard. 54: 191. 1967. Cleidion ni- caraguense Hemsl., Biol. centr. amer. Bot. 3:
56
FIELDIANA: BOTANY
130. 1883. Gitara panamensis Croizat, J. Ar- nold Arbor. 26: 192. 1945. Figure 12.
Shrubs or small treelets l-5(-7) m tall, dioecious, leafy stems 0.9-4 mm thick, with thin whitish hairs, glabres- cent and gray in age, epidermis exfoliating in longitudinal strips on older stems; stipules 1.5-6 mm long, 0.8-1.8 mm broad at base, triangular to lanceolate, glabrous or puberulent abaxially, persisting and brown, veins par- allel and prominent or obscure. Leaves with petioles 2- 6 mm long, ca. 1 mm thick, densely strigose with stiff ascending or erect hairs 0.2-0.6 mm long; leaf blades 8- 2 1 cm long, 3-7 cm broad, narrowly elliptic-oblong, nar- rowly ovate-elliptic or elliptic, apex acuminate with a narrowed tip 7-25 mm long, margin distally crenate- dentate with gland-tipped teeth 0-4 mm long, base grad- ually narrowed and cuneate, slightly rounded at the pet- iole, drying chartaceous and dark green to greenish gray or brown, glabrous or minutely puberulent on the veins above, glabrous beneath but with some hairs along the veins and in the vein axils (domatia), with 4-7 major secondary veins on each side. Inflorescences 1-3 on ax- illary short-shoots, unisexual, axillary or pseudotermin- al, $ 0.5-5 cm long, 9 ca. 1 cm long but elongating in fruit, racemose, subtended at the base by a series of imbricate stipules, peduncles 3-8 mm long, 0.3-0.4 mm thick, <5 flowers in alternate fascicles of 2-4, 9 flowers 2- 4 and alternate along the strigulose unbranched or few- branched rachis, bracts to 2 mm long, acute, <3 pedicels to 3 mm long, 9 pedicels ca. 1 mm long. Male flowers white or yellowish, sepals 3, 1.5-3 mm long, 0.8 mm broad at the base, pubescent on the exterior, stamens ca. 21, filaments 1.3-2.5 mm long, 0.1-0.2 mm thick, erect, drying orange-brown, anthers 0.2-0.4 mm long, 0.2-0.3 mm broad, connective apex with a minute (0. 1 mm) tuft of stinging hairs (difficult to see). Female flowers white or yellowish, sepals 1.3-2 mm long, 0.5-0.8 mm broad, narrowly acute; ovary 1-1.7 mm long, covered with stiff ascending hairs, style column 0.4-1.2 mm long, style branches 1.3-2.7 mm long, recurved, papillose. Fruits 5-6 mm long, 8-10 mm broad, deeply 3-lobed and breaking into cocci 4-5 mm broad, surfaces with sharp stinging hairs; seeds 4—4.5 mm long, subglobose.
Plants of evergreen forest formations on both the Pacific and Caribbean slopes, 0-700 m ele- vation (to 1000 m in Nicaragua). Flowering in January-July; fruiting in March-October. While the species is not often collected in Costa Rica, it can be locally common (as at Volcan Orosi). The species ranges from Guatemala to Peru.
Acidoton nicaraguensis is recognized by the nar- row short-petiolate leaves with prominent gland- tipped teeth, domatia in vein axils, slender axillary spicate/racemose inflorescences, $ flowers with many closely congested filaments, minute anthers, and fruits with rounded cocci and stinging hairs. This species appears to be common in eastern Nic- aragua; it has been called mala in southeastern Honduras, perhaps because of the stinging hairs, which may be present on the foliage as well as on
the flowering parts. The South American A. \e- nezolanus (Croizat) Webster may be conspecific.
Actinostemon Martius ex Klotzsch
REFERENCE— E. Jablonski, Notes on Neotropi- cal Euphorbiaceae 4. Monograph of the genus Ac- tinostemon. Phytologia 18: 213-240. 1969.
Trees and shrubs, monoecious, stems glabrous or pu- berulent, inflorescence buds enclosed in a tight series of imbricate stipule-like bud-scales; stipules lateral. Leaves alternate, simple, usually short-petiolate, often coria- ceous or subcoriaceous, usually glabrous, margins entire, venation pinnate. Inflorescences terminal or axillary, solitary or 2-3/node, bisexual or unisexual, racemes with an unbranched rachis, at first subtended by imbricate deciduous bracts; <5 flowers usually 2-3/bract, each flower borne on a thin pedicel; 9 flowers 1 (2-3) and proximal on the rachis, borne on long pedicels. Male flowers mi- nute, calyx and corolla absent, disk absent; stamens 2- 1 6 or many, filaments free, anthers erect, ovoid, dehisc- ing longitudinally; pistillode absent. Female flowers small, calyx absent or represented by 1-3 minute lobes, corolla and disk absent, staminodes absent; ovary 3-locular, smooth or tuberculate, ovules 1/locule, styles united for a short or longer length, free and recurved distally, simple (undivided). Fruits capsules, glabrous to sericeous, breaking into 3 2-valved cocci, columella persisting; seeds subglobose, carunculate, endosperm fleshy, cotyledons plane and flat.
A Neotropical genus of 1 3 species; most species are found in southeastern South America, with outliers in Cuba, the Lesser Antilles, Venezuela, and the Amazon basin. The strobilus-like inflo- rescences are at first enclosed in a tight series of imbricate bracts. This, in addition to the virtually naked flowers and restriction to dry deciduous lowlands in Costa Rica, help distinguish our rep- resentative of this genus. In appears that the pro- tection of the young floral organs by the bud-scale- like bracts compensates for the loss of a protective perianth. Webster (1 994b and earlier) includes this genus in Gymnanthes.
Actinostemon caribaeus Griseb., Abh. Ges. Wiss. Gottingen 7: 168. 1857. Excoecaria caribaea Griseb., Fl. Brit. W. Ind. 51. 1864. A. concolor var. caribaeus (Griseb.) Mull. Arg. in DC., Prodr. 15(2): 1193. 1868. Figure 25.
Small trees or shrubs 2-5 m tall, to ca. 10 cm trunk diam., leafy stems 1.4—4 mm thick, glabrous, longitu- dinally striate; stipules ca. 3 mm long, glabrous, quickly caducous and leaving small scars, shoot-apices covered by stipule-like glabrous bud-scales (3-7 mm long) that dry dark reddish brown and leave a circle around the
BURGER & HUFT: FLORA COSTARICENSIS
57
stem when they fall. Leaves glabrous, petioles 3-7 mm long, 0.5-2 mm thick, drying brown; leaf blades 5-1 1 cm long, 1.8-4.7 cm wide, elliptic-obovate to narrowly obovate or narrowly elliptic-oblong, apex obtuse to acute, often with a small (0.3 mm) glandular tip, margin entire and drying slightly revolute, tapering gradually to the cuneate base, slightly (0-3 mm) lobed or auriculate at the petiole, drying subcoriaceous and grayish, 2° veins 8- 11 /side and loop-connected distally, with usually 4 dark flat glands (0.3-0.4 mm diam.) near the base be- neath. Inflorescences axillary or pseudoaxillary, solitary, bisexual or <5, 1.5-4 cm long, with a single unbranched racemose axis, peduncle 1-5 mm long, with a solitary proximal 2 flower subtended by stipule-like bracts, distal rachis 0.3-0.7 mm thick and winged, yellowish, 6 flowers subtended by linear bracts 2-4 mm long. Male flowers lacking perianth (naked), borne on a pedicel 0.5-3 mm long, with 2-5 slender filaments 0.3-0.8 mm long, an- thers 0.3-0.5 mm long. Female flowers glabrous, lacking perianth, pedicel 1-15 mm long and continuous with the ovary base, ovary ca. 2 mm long, 0.8 mm diam., style base 2-4 mm long (to 5 mm in fruit), style branches 3- 5 mm long, papillose adaxially. Fruits 10-12 mm long, 9-12 mm diam., greenish in life, borne on pedicels 1-5 cm long, outer wall of cocci 0.5 mm thick, columella 7 mm long, 4 mm wide at apex; seeds ca. 6.8 x 4.5 x 3.5 mm, oblong, caruncle 1 mm high.
Plants of deciduous lowland and adjacent partly deciduous forests, 100-700 m elevation (to 1000 m in Nicaragua). Flowering in June (Hammel 17777 CR, Zamora et al. 1255 CR, F); fruiting in August (Q. Jimenez et al. 868 CR) and September (Q. Jimenez 385 F). This species has only recently been collected in northern Guanacaste Province, Costa Rica, and central Nicaragua; this species also occurs in the Lesser Antilles and northern Venezuela.
Actinostemon caribaeus is recognized by its lack of pubescence, often narrowly obovate leaf blades with glandular punctations in the lower lamina base, slender little inflorescences with stalked 9 flowers and clustered $ flowers, and flowers lacking calyx or corolla (naked). The 9 flower exhibits al- most no differentiation between pedicel and ovary base or ovary apex and stylar column. Thus, the $ flowers appear as stipitate pistils. The narrowly ovoid apical buds with overlapping scales and acute apex are also distinctive. This species is closely related to A. brachypodus (Griseb.) Urban of Cuba and A concolor (Spreng.) Mull. Arg. of southeast- ern Brazil and Paraguay.
Adelia Linnaeus
Shrubs or small trees, dioecious, branchlets often with spines (leafless short-shoots), pubescence simple, gla- brescent; stipules small and paired at the leaf base. Leaves
alternate, simple, petiolate; leaf blades pinnately veined, margins entire, membranaceous to chartaceous, with tufts of hairs (domatia) in the vein axils beneath and along some of the major veins, pellucid-punctate. Inflores- cences axillary, unisexual, $ flowers fasciculate on re- duced short-shoots, small, pedicels slender and short to long, often articulate in the middle; 2 flowers paired in the axils and long-pedicellate. Male flowers with calyx of 4-5 parts, valvate in bud, petals absent, disk extra- staminal and annular (rarely of 5 glands), adnate to the calyx; stamens 6-30, filaments free or becoming connate basally, slender, anthers versatile, dorsifixed, with par- allel divergent thecae, dehiscing longitudinally, a small pistil lode sometimes present at the apex of the staminal column (Croat, 1978). Female flowers with 5-7 narrow sepals, reflexed at anthesis, petals and staminodes ab- sent, disk annular and pubescent; ovary usually 3-lobed and 3-locular, styles 3, free, laciniate, ovules 1/locule. Fruits capsular, 3-lobed, puberulent, usually separating into 3 2-valved cocci with loculicidal dehiscence; seeds mostly carunculate.
A genus of 10-12 Neotropical species, best rep- resented in the West Indies.
Adelia triloba (Mull. Arg.) Hemsl., Biol. centr. amer. Bot. 3: 130. 1883. Ricinella triloba Mull. Arg., Linnaea 34: 153. 1866. Figure 31.
Shrubs or small trees, 3-15 m tall, trunk 12-20(-30) cm thick, leafy stems 1-3.5 m thick, minutely (0.1 mm) puberulent or glabrous, yellowish to pale gray, with small (0.3 mm) rounded lenticels, straight spines 8-22 mm long sometimes present, 1-2 mm thick at the base; stip- ules 0.5-3.5 mm long, triangular to linear-subulate, gla- brous and lustrous on the exterior, deciduous. Leaves with petioles 3-7(-9) mm long, 0.4-1.5 mm thick, mi- nutely puberulent or glabrous, glands absent; leaf blades 8-17(-23) cm long, 2.5-7(-9) cm broad, elliptic to ellip- tic-oblong or narrowly obovate, apex acuminate, grad- ually narrowed to the cuneate base, often slightly round- ed at the petiole, drying chartaceous and greenish or grayish, glabrous and the major veins prominent above (dry), with whitish hairs 0.2-0.4 mm long usually along major veins beneath, 2° veins 3-6/side, vein axils often lined by hairs (domatia) beneath. Male flowers in fas- cicles of up to 50 flowers, bracts to 2 mm long, pubescent at the base, pedicels 3-10 mm long, slender, minutely puberulent, flower buds ca. 2 mm diam., globose; sepals 4-5, 2-2.5 mm long, pale yellowish; stamens 6-30, sta- minal column short or not apparent, filaments 0.5-1.8 mm long, filiform, anthers 0.4 mm long, 0.5-0.6 mm broad. Female flowers pendulous on slender pedicels 1- 3 cm long (to 7.5 cm in fruit), 0.3-0.5 mm thick, glabrous or minutely puberulent, sepals 4-6, 3-6 mm long, 0.5- 1 mm broad; ovary ca. 2 mm long, 2.5-3 mm wide, 3-lobed, densely puberulent with erect hairs 0. 1-0.2 mm long, styles 1.5-3 mm long, laciniate distally. Fruits 6- 9 mm long, 8-12 mm wide, oblate and slightly to deeply 3-lobed distally, pubescent, pendulous on the slender pedicels, splitting from the top, persisting columella 3- 4.2 mm long, 0.7 mm thick, expanded at apex; seeds 3.8-5 mm long, subglobose, with or without a mottled color surface, smooth, with a linear longitudinal raphe.
58
FIELDIANA: BOTANY
Plants of evergreen and partly deciduous forest formations of both the Pacific and Caribbean slopes, 10-1000 m elevation. Flowering in De- cember-February; fruiting in January-April. The species ranges from southern Nicaragua to eastern Panama.
Adelia triloba is recognized by the spiny stems (when present), fruits pendulous on long slender pedicels, persisting columella, the fasciculate $ flowers, leaves with pubescent little domatia, and restricted flowering/fruiting period. In addition, the leaves are short-petiolate and pellucid-punc- tate. Some collections have distinctively long ( 1 5- 20 cm) narrow (ca. 6 cm) leaf blades. The plants are called espino de playa in Nicaragua. This spe- cies is closely related to Adelia barbinervis Schldl. & Cham. (Mexico to Nicaragua), but that species lives in seasonally dry deciduous and open sec- ondary forests and has smaller leaves than A. tri- loba, and the fruits are not deeply lobed.
Adenophaedra (Miiller Argoviensis) Muller Argoviensis
Shrubs or small trees, dioecious, hairs simple, sap not milky; stipules paired at the leaf base. Leaves alternate, simple, petiolate, pinnately veined, entire or dentate with gland-tipped vein endings, with laminar glands. Inflo- rescences axillary or terminal, 1-3/node, spiciform, bracts without glands, subtending 1 9 flower or several closely congested $ flowers, flowers pedicellate. Male flowers globose in bud, sepals 3, valvate in bud, petals absent, disk absent; stamens 2-3, alternate with sepals, filaments very short, anthers ovate, dehiscing longitudinally and introrse, connective enlarged distally; pistillode absent or minute. Female flowers with 6 sepals in 2 series, in- terior whorl smaller, imbricate in bud, petals absent, staminodes absent, disk annular and 3-lobed; ovary 3-lobed, 3-locular, style short or minute with broad ses- sile stigmas, ovules 1/locule. Fruits capsular, promi- nently 3-lobed, depressed at the apex, separating into 3 2-valved cocci; seeds globose, ecarunculate, surfaces smooth.
A genus of three South American species with one reaching central Costa Rica. The pendulous unisexual spike-like inflorescences, minute $ flow- ers with few subsessile stamens, and 9 flowers with six imbricate sepals and broad sessile stigmas help distinguish the genus.
Adenophaedra grandifolia (Klotzch) Mull. Arg. in Mart., Fl. Bras. 11 (2): 386. 1874. Tragia gran- difolia Klotzsch, London J. Hot. 2: 46. 1843. Bernardia grandifolia (Klotzsch) Mull. Arg., Linnaea 34: 173. 1865. Cleidion denticulatum
Standl., Publ. Field Columb. Mus., Bot. Ser. 4: 2 1 8. 1 929. Bernardia denticulata (Standl.) Web- ster, Ann. Missouri Bot. Gard. 54: 200. 1967. Figure 13.
Shrubs or small trees, 2-6(-8) m tall, leafy stems 1-6 mm thick, with stiff ascending hairs 0.2-0.5 mm long, glabrescent, becoming dark reddish brown; stipules 3- 13 mm long, 1-2 mm wide at the base, oblong to nar- rowly lanceolate, densely strigose to glabrous, deciduous. Leaves with petioles 5-18 mm long, 1.3-2.3 mm thick, strigose and glabrescent; leaf blades ( 1 0-) 1 8-33 cm long, (2-)5-13 cm wide, narrowly obovate-oblong to oblan- ceolate or elliptic-oblong, apex short-acuminate or cau- date-acuminate, narrowed tip 4-14 mm long, margins dentate with 1 9-28 teeth/side (entire along basal third), teeth 0.5-1 mm high, tapering gradually to a cuneate base with the margin sometimes thickened near the base, flat rounded imbedded glands often present near the lam- ina base adaxially, drying stiffly chartaceous to subcor- iaceous, with thin whitish hairs ca. 0.5 mm long on the upper surface and glabrescent, with hairs 0.2-0.5 mm long beneath, 2° veins 7- 11 /side. Male inflorescences axillary, 1-3, $ to 26 cm long with up to 60 glomerules separated by 4—12 mm and with 2-6 flowers/glomerule, fallen flowers leaving stiff persistent pedicels to 1 mm long; $ flower buds ca. 0.7 mm diam., 0.5 mm long, sepals 0.8 mm long, 0.6 mm broad at the base, with sharp straight hairs on the outer surface, glabrous within; stamens 3, subsessile, anthers 0.2 mm broad. Female inflorescences to 12 cm long with 4-7 flowers, rachis densely hirsute or strigose with stiff whitish hairs 0.2- 0.4 mm, bracts 1-1.5 mm long; 2 flowers with perianth parts ca. 2.2 mm long, 2 mm wide at the base, outer surface with stiff ascending hairs, stigmas ca. 0.5 mm long and equally broad. Fruits 6-9 mm long, 13-18 mm broad, deeply 3-lobed, borne on peduncles to 5 mm long, cocci ca. 12 x 8 mm, columella 3-6 mm long, to 7 mm broad distally, with winged erose axis; seeds 7-9 mm long, 6.3-7.5 mm wide, oblong, smooth, with mottled coloring.
Plants of wet evergreen cloud forest formations of the Caribbean slope, ( 1 00-)300-900 m eleva- tion. Possibly flowering throughout the year; fruit- ing in December-May. This species ranges from central Costa Rica (83°28'W) to Venezuela.
Adenophaedra grandifolia is recognized by the larger oblanceolate leaves on short thick petioles, gland-tipped dentate leaf margin, unisexual spi- ciform inflorescences, and minute flowers. Com- pare the superficially similar Caryodendron an- gustifolium.
Alchornea Swart/
Trees or shrubs, dioecious in Central American spe- cies, glabrous or puberulent with simple or stellate hairs; stipules free, small or obscure. Leaves alternate, simple, petioles usually thickened near the blade; leaf blades
BURGER & HUFT: FLORA COSTARICENSIS
59
usually dentate with small rounded teeth, venation pin- nate or palmate (tripliveined), usually with glands in the leaf tissue near the base, domatia present or absent. Male inflorescences axillary, 1-3/node, spicate or with simple lateral branches, <? flowers many, subsessile or short- pedicellate on the spicate axes, bracts subtending 1-6 flowers; $ flowers with perianth globose to oblate in bud, splitting into (2-)3-4(-5) valvate calyx lobes, petals ab- sent, disk absent or confluent with stamen bases, stamens usually 8 in Central America, in 2 whorls of 4, filaments free, usually shorter than the anthers, anthers oblong and dorsifixed, dehiscing longitudinally, introrse; pistillode absent. Female inflorescences axillary or terminal, usu- ally I/node, usually spicate with an unbranched rachis or sometimes with a few basal branches, bracts usually subtending solitary (2-3) flowers, pedicels short or ab- sent; 9 flowers with usually 4 (3-6) imbricate sepals, petals absent, staminodes absent, disk absent; ovary with 2 (3-4) locules, ovules 1/locule, styles 2 (3-4), united
only near the base, style branches rarely bifid at apex. Fruits capsules with fleshy exterior, globose, usually splitting into 2 2-valved cocci, columella present but caducous; seeds tuberculate, ecarunculate, with promi- nent ventral raphe, endosperm present, cotyledons straight.
A pantropical genus of ca. 50 species. The genus is distinguished by its dioecious plants, flat round- ed glands near the lamina base, frequent presence of domatia in vein axils, and subsessile flowers and fruits on long slender few-branched axes. The inflorescences are either simple and spiciform or panicle-like with spiciform branches. Individual collections vary considerably within species, and this often makes identification difficult.
Key to the Species of Alchornea
1 a. Largest leaves < 6 cm long (in Costa Rica) [subcoriaceous and glabrous, rounded or bluntly acute distally, venation tripliveined or pinnate; rarely collected from 900 to 1 900 m in Costa Rica and
Panama] A. triplinervia
Ib. Largest leaves > 6 cm long 2
2a. Leaves drying chartaceous, grayish green to dark green 3
2b. Leaves drying coriaceous or subcoriaceous, often yellowish or dark gray [venation pinnate or sub- palmate] 4
3a. Venation pinnate, basal 2° veins not prominent and not reaching the middle of the blade, leaf blades usually elliptic to oblong; young stems glabrous; 0-800 m elevation . . A. costaricensis 3b. Venation palmate or subpalmate, basal 2° veins prominent and reaching the center of the blade, leaf blades usually ovate to ovate-elliptic; young stems densely puberulent; 500-1200 m ele- vation A. glandulosa
4a. Leaf blades 5-24 cm wide, usually broadly ovate to oblong (elliptic-oblong in the lowlands); style
branches to 0.6 mm wide; commonly collected in Central America, 40-2300 m elevation
A. latifolia
4b. Leaf blades 2-7.5 cm wide, usually narrowly ovate; style branches to 1 mm wide; rarely collected in Central America at 1600-2200 m elevation A. grandiflora
Alchornea costaricensis Pax & K. Hoffm., Pflan- zenreich 4. 147. 7: 235. 1914. A. costaricensis f. longispicata Pax & K. Hoffm., Pflanzenreich 4. 147. 14: 20. 1920. Figure 12.
Trees 4-1 5(-27) m tall, trunks usually less than 30 cm diam. (to 70 cm), branchlets terete and glabrous; stipules to 0.5 mm long, triangular. Leaves with petioles 13-35 (80) mm long, 0.7-1.5 mm thick, to 1.8 mm thick near the blade, glabrous or minutely papillate-puberulent; leaf blades 7-18 cm long, 3-6.5 cm wide, elliptic to ovate- elliptic or elliptic-obovate, apex long-acuminate, tip 1- 3 cm long, margin prominently serrate with teeth 5-15 mm apart, base acute to obtuse, glands often on the edge at the base, drying chartaceous, glabrous above, glabrous or minutely (0.05 mm) papillate-puberulent beneath, ve- nation pinnate, 2° veins 5-8/side. Male inflorescences 1-3/axil, 4-8 cm long, unbranched spikes (rarely with
short basal branches), rachis 0.3-0.5 mm thick, minutely stellate puberulent, flowers in sessile glomerules of 2-5; $ flowers white or yellowish, buds 1.2-1.5 mm diam.; filaments short (0.3 mm) and untied at base, anthers 0.5- 0.6 mm long, 0.4 mm wide. Female inflorescences I/ axil, 2-5(-10) cm long, unbranched (or branched when distal leaves fail to develop), rachis 0.5-0.7 mm thick, minutely puberulent; 9 flowers solitary, subsessile, calyx lobes 4, ca. 1 mm long, ovary 1-1.5 mm long, 0.7-1 mm diam., densely puberulent, styles 7-10 mm long, ca. 0.4 mm thick. Fruits 5-7 mm long, 6-9 mm wide, rounded and bilobed, pinkish green to reddish brown, pedicels to 3 mm long; seeds 4-6 mm diam., subglobose, surface irregularly rugose.
Plants of lowland rain forest formations, 0-800 m elevation. Flowering in January-June; fruiting in March-July. This species ranges from the Ca-
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FIELDIANA: BOTANY
ribbean coast of Honduras to eastern Panama and Colombia.
Alchornea costaricensis is distinguished by its chartaceous serrate glabrescent leaves with pin- nate venation, simple (rarely branched) $ spikes, and lowland habitat. It has been called fosforo in Costa Rica. This species is similar to A. glandu- losa, but that species has palmate venation and 3° veins that are more prominent and often conspic- uously parallel. Specimens of two tall (27 m) trees from mangrove forest in Honduras appear to be this species (Saunders 914 & 931). These plants are easily mistaken for species of Sorocea (Mo- raceae).
Alchornea glandulosa Poepp. in Poepp. & Endl., Nov. gen. sp. PL 3: 18, t. 221. 1841. A. pittieri Pax, Bot. Jahrb. Syst. 33: 291. 1903. A. glan- dulosa var. pittieri (Pax) Pax, Pflanzenreich IV. 147. VII (Heft 63): 235. 1914. Figure 24.
Trees 8-22 m tall, leafy stems 1.5-5 mm diam., dense- ly hirsutulous with short (0.1-0.3 mm) simple and stel- late hairs; stipules 0.5-1 .5 mm long, hirsutulous. Leaves with petioles 1.3-5(-7) cm long, 0.7-1.5 mm thick, ca. 1.9 mm thick near the apex, stellate hirsutulous; leaf blades 5-16.5 cm long, 2-9 cm wide, ovate-elliptic to elliptic, ovate or narrowly ovate, tapering gradually to the acuminate apex, tip 4-17 mm long, marginal teeth 8-17/side, rounded, base obtuse to rounded and slightly subcordate, with 2-6 flat rounded glands in the blade near its base, drying chartaceous, glabrescent above ex- cept for small hairs on the midvein, minutely (0. 1 mm) stellate-puberulent beneath, with tufted domatia in ma- jor vein axils beneath, venation palmate with basal 2° veins reaching the middle of the blade, distal 2° veins 2-3/side, 3° veins subparallel. Male inflorescences 5-12 cm long, spicate or with lateral branches to 4 cm long, rachis 0.5-0.8 mm diam., glomerules with 2-5 subsessile flowers; $ flower buds 1 .2 mm diam., anthers ca. 0.5 mm long. Female inflorescences 4-17 cm long, unbranched spikes (rarely branched), rachis 0.6-1 mm thick, stellate- puberulent, flowers sessile and solitary; $ flowers with calyx lobes ca. 0.5 mm long, ovary 1.5-2 mm long, 1.2- 2.2 mm diam., ovoid, densely white or yellowish stellate- pubescent, styles 5-7 mm long, 0.3-0.4 mm thick; pu- berulent along abaxial side. Fruits 5-6 mm long, 7-8 mm wide, bilobed, becoming dark; seeds with reddish covering.
Plants of evergreen lower montane forest for- mations; 500-1500 m elevation. Flowering occurs in January-March and September-October; fruit- ing in October-December. This species ranges from Costa Rica to the Amazon basin.
Alchornea glandulosa is recognized by the char- taceous ovate leaves with as many as six small glands imbedded in the blade near the base, stel- late-pubescent young stems, and mid-elevation
habitats. Collections from Costa Rica and Panama belong to variety pittieri, distinguished by smaller glands than those found in typical South American collections.
Alchornea grandiflora Mull. Arg., Linnaea 34: 170. 1865.
Trees 6-25 m tall, leafy stems 1.6-5 mm thick, with scattered minute (0.05-0. 1 mm) flat stellate hairs, gla- brescent and drying dark; stipules 0.5-1 mm long, tri- angular. Leaves with petioles 17-65 mm long, 1-2 mm thick, glabrous and drying dark; leaf blades 5-13 cm long, 2-7.5 cm wide, broadly elliptic to ovate, apex ob- tuse, marginal teeth 7-1 I/side, prominent, base cuneate to obtuse, margin often recurved near the petiole, drying subcoriaceous, glabrescent above and below, venation palmate with basal 2° veins reaching middle of the blade, distal 2° veins 3-4/side, 3° veins prominent and sub- parallel, basal vein axils forming cavities beneath, distal vein axils with tufted domatia. Male inflorescences 2- 1 1 cm long, with lateral branches 1-4 cm long, central rachis 0.5-1 mm thick, bracts ca. 1 mm long; $ flower buds 1.5-2 mm diam., calyx lobes ca. 1 mm long, tri- angular, glabrous except on edge, stamens 6-8. Female inflorescences 4-6 cm long, unbranched, rachis 0.6-1.4 mm thick, with ca. 6-12 flowers, 2 flowers with calyx lobes to 1 .8 mm long, acute, ovary 1.5-2 mm long, densely pubescent, style branches 4-18 mm long, ca. 1 mm wide. Fruits 6-7 mm long, ca. 8 mm wide, bilobed, columella ca. 5 mm long, 0.8 mm broad.
Plants of montane and lower montane evergreen forest formations, 1 600-2200 m elevation in Pan- ama (400-2300 m in South America). Flowering in June-July in Panama. This species is said to range from Costa Rica to Bolivia (see below).
Alchornea grandiflora is recognized by its 9 flow- ers with thick style branches, larger fruits, stiff gla- brous leaves with prominent domatia, and unusu- al leaf bases. In larger leaves, the basal secondary veins have deep depressions in their axils and the leaf margin is re volute. We have not seen material from Costa Rica, but a syntype (Hoffman 530 G) was collected in Costa Rica and several collections are cited from Panama (Webster & Huft, 1988). This species can be mistaken for A. latifolia, but that species tends to grow at lower elevations in southern Central America.
Alchornea latifolia Sw., Prodr. 98. 1788. Fl. Ind. Occ. 2: 1 154, t. 24. 1800. A. platyphylla Mull. Arg., Linnaea 34. 171. 1865 (fide Standl. 1937 who may not have seen the type: Oersted, Ta- caca, Centr. Amer., herb. B). A. cyclophylla Cro- izat, J. Arnold Arbor. 24: 166. 1943. Figure 24.
Trees 6-25 m tall, trunks to 45 cm diam., leafy stems 2-7 mm thick, glabrous or with minute (0. 1 mm) scurfy
BURGER & HUFT: FLORA COSTARICENSIS
61
hairs; stipules 1 mm long and triangular or obscure. Leaves with petioles 2.5-8(-13) cm long, 1.5-2.7 mm thick, to 4 mm thick below the blade, usually glabrous, drying dark, glands absent on the petiole but 2-4 glands present in the leaf tissue near the base of the blade; leaf blades 8-24(-34) cm long, 5-19(-24) cm wide, ovate to ovate- oblong or ovate-orbicular (elliptic-oblong at lower ele- vations), apex rounded to obtuse, with a small (0-5 mm) acuminate tip, marginal teeth 8-20/side, 1-2 mm high, base obtuse to rounded and truncate or subcordate, dry- ing coriaceous, glabrous above, glabrous or with scat- tered minute (0.05 mm) flat stellate hairs beneath, ve- nation palmate or subpalmate (pinnate at lower eleva- tions), basal 2° veins reaching middle of blade (at higher elevations), 2° veins 5-7/side, 3° veins subparallel, tufted domatia or gland-like areas sometimes present in the leaf axils. Male inflorescences to 30 cm long, paniculate with few to many alternate unbranched lateral branches 1-9 cm long, rachis 1.2-2.2 mm thick, glomerules with 3-7 flowers; $ flower buds ca. 1.5 mm diam., anthers 0.8-1.2 mm long, 0.6-0.8 mm wide. Female inflores- cences 5-20(-50) cm long, unbranched or with few to many branches to 15 cm long, rachis 2-3 mm thick, minutely stellate puberulent, bracts to 1 mm long, tri- angular, pedicels 0.5-1.5 mm long; 9 flowers with calyx lobes ca. 1 mm long, acute, sparsely and minutely pu- berulent, ovary 1.5-2.5 mm long, 1-2 mm diam., style column 2-3 mm long, style branches 7-1 1 mm long, 0.4-0.5 mm wide, white. Fruits 5-7 mm long, 7-1 1 mm wide, bilobed, becoming red; seeds 5-6 mm long.
Plants of lower montane evergreen forest for- mations, (40-)300-1600(-2300) m elevation. Flowering in January-July; fruiting in March-Sep- tember. This is the most commonly collected spe- cies ofAlchornea in Costa Rica, with most spec- imens from above 800 m elevation. This species ranges from Mexico and the West Indies to Ven- ezuela and Peru.
Alchornea latifolia is distinguished by its larger broad coriaceous leaves, larger paniculate $ inflo- rescences with spike-like distal branches, and rounded fleshy fruits terminated by two persisting style branches. The highland collections with their broadly ovate leaves, subpalmate venation, and usually simple $ inflorescences differ strikingly from specimens collected below 500 m elevation with elliptic-oblong leaves, pinnate venation, and <3 in- florescences with many lateral branches. There ap- pears to be an altitudinal cline in southern Central America, with specimens from 500 to 900 m being intermediate between the highland and lowland collections, but this pattern may be obscured by considerable individual variation.
Alchornea triplinervia (Sprengel) Mull. Arg. in DC., Prodr. 15 (2): 909. 1866. Antidesma tripliner- vium Sprengel, Neue Entdeck 2: 116. 1821. A. guatemalensis Lundell, Wrightia 6: 10, pi. 20. 1978.
Trees 6-20 m tall, leafy stems 1.5-5 mm thick, essen- tially glabrous; stipules rudimentary. Leaves with peti- oles 8-22 mm long, 0.7-1 .3 mm thick, slightly thickened at apex and base, glabrous; leaf blades 3-6 cm long, 2- 3 cm wide, broadly elliptic-oblong to elliptic-obovate, apex rounded to bluntly acute, margin entire or with 4-
5 small rounded teeth, base rounded to obtuse, with 2-
6 round flat glands near the base, drying subcoriaceous and grayish, glabrous above and below, venation pinnate with prominent basal 2° veins but these not reaching the middle of the blade, 2° veins 3-5/side. Male inflores- cences to 10 cm long, with lateral branches to 3.5 cm long, rachis 0.5-1 mm thick, stellate-puberulent, glom- erules with 1-4 sessile flowers; <3 flower buds 1-1.5 mm diam., anthers ca. 0.8 mm long. Female inflorescences to 8 cm long, rachis 0.6-0.8 mm thick, with minute stellate or scurfy hairs, bracts 0.5 mm long; 9 flowers solitary, calyx 1.2-1.8 mm long, lobes 0.8-1 mm long, glabrous, ovary 1-1.5 mm long, 0.6-1 mm diam., with minute stellate hairs, style branches 3-7 mm long, 0.4- 0.5 mm thick. Fruits ca. 3 mm long, to 5.5 mm wide.
Rarely collected plants of montane (1600-1900 m) forests in Costa Rica but from lower (500-900 m) elevations in Guatemala and Panama. Flow- ering in June-September; fruiting in September. In Costa Rica, the species is only known from near Desamperados, Altos de Tablazo (Utley & Utley 3039 & 5209 F), and Monteverde (Haber 551 CR, F). It is also known from a single collection in Guatemala (Lundell & Contreras 21201 F, isotype of A. guatemalensis) and several collections from Panama. The species ranges to eastern Brazil.
Alchornea triplinervia is recognized by its small stiff glabrous leaves with three prominent basal veins, short 9 sepals, and restricted habitat. The decision to place these few Central American col- lections under A. triplinervia and to submerge A. guatemalensis should be considered tentative.
Alchorneopsis M tiller Argoviensis
Trees, often becoming part of the forest canopy, di- oecious, hairs simple; stipules absent. Leaves alternate, simple, petioles with slightly thickened tissue at base and apex, blades with flat glands near the base, entire or subentire, venation tripliveined, pit domatia sometimes present in the vein axils beneath. Inflorescences axillary, 1-3/axil, unisexual, spiciform with long slender un- branched rachis, flowers or glomerules not crowded along the rachis, subtended by minute bracts; <5 flowers in al- ternate glomerules of 1-5 pedicellate flowers, 9 flowers solitary or few along the rachis, pedicellate. Male flowers small, globose in bud, calyx splitting into 3-4 valvate parts, petals absent, disk large and annular, hirsutulous; stamens 4-8, often 6 in 2 whorls, filaments free, anthers dehiscing longitudinally and introrse, outer thecae valves larger than the inner, connective enlarged and glandular; pistillode minute, 3-lobed, glabrous. Female flowers small, sepals 4-5, petals absent, disk annular (often difficult to
62
FIELDIANA: BOTANY
see), hirsutulous and merged with the base of the ovary, staminodes absent; ovary 3-locular, ovules 1/locule, style column short, style branches 3, recurved and undivided, papillate. Fruits capsular, small, rounded and breaking into 3 cocci split only at the apex, columella persistent or not; seeds flattened, ecarunculate, outer coat fleshy, inner coat striate-reticulate, cotyledons broad and flat.
A tropical American genus of three closely re- lated species. The genus is very similar in ap- pearance ioAlchornea, but it lacks the stellate hairs of Alchornea. In addition, $ inflorescences of Al- chorneopsis are never branched and the <3 flowers have a small pistillode. Seeds of the two genera are very different, and the three short styles of Alchorneopsis differ from the typically two long styles of Alchornea.
Alchorneopsis floribunda (Benth.) Mull. Arg., Lin- naea 34: 156. 1865. Alchornea glandulosa var. floribunda Benth., Hooker's J. Bot. Kew Gard. Misc. 6: 331. 1854. Figure 24.
Trees (3-) 10-40 m tall, trunks to 1 m dbh, brownish with vertical fissures, leafy stems 1.5-3.5 mm thick, mi- nutely (0.05-0. 1 mm) puberulent, glabrescent and pale brown to dark gray; stipules none. Leaves with petioles 10-42 mm long, 0.8-2 mm thick, usually glabrous, slightly thickened and drying darker near the base and apex; leaf blades 7-18 cm long, 2-7 cm wide, elliptic, elliptic-ob- long or oblong-obovate, apex short-acuminate with blunt tip 4-10 mm long, cuneate to acute at the base, margin crenate with 6-12 gland-tipped lobes 0.3-1 mm high, drying stiffly chartaceous to subcoriaceous, glabrous above and below or very minutely puberulent on the midvein, 2° veins 2-4/side with the basal pair strongly ascending and reaching beyond the middle of the blade, 3° veins subparallel and mostly perpendicular to the midvein, flat rounded glands sometimes present near the base, narrow slit-like pit domatia (0.5-1 .2 mm long) sometimes pres- ent in the basal vein axils beneath. Male inflorescences 5-14 cm long, rachis 0.5-0.8 mm thick and minutely puberulent, with alternate fascicles of 1-7 flowers on pedicels 1-2 mm long, subtended by bracts ca. 0.5 mm long; $ flowers white to pale yellowish green, ovoid in bud and 1.1-1.3 mm long, sepals 1.1-1.5 mm long, re- flexed, sparsely puberulent on the exterior, glabrous on the interior, disk 0.3-1 mm high including the erect whit- ish or yellowish hairs; stamens usually 6, filaments 0.7- 1 .8 mm long, slender, anthers 0.3-0.6 mm long; pistilode 0.4-0.6 mm long, 3-parted, hidden within the hairs. Female inflorescences 4-6 cm long, usually I/axil, rachis ca. 0.6 mm thick, minutely puberulent, pedicels ca. 1 mm long, densely puberulent; $ flowers with sepals 0.3- 0.9 mm long, triangular, ovary ca. 2 x 1 .8 mm, minutely pubescent, style column ca. 0.2 mm long, style branches ca. 0.6 mm long. Fruits ca. 4 mm long, 3-3.5 mm diam., subglobose, smooth and rounded, splitting into 3 cocci
ca. 3 mm broad; seeds often adhering to each other, 2.2- 2.4 mm long, 2.1-2.5 mm broad, ca. 1.2 mm thick, ovoid-lenticular, pale yellowish, abaxial surface with 10- 1 2 longitudinal ridges, with a red aril-like seed coat.
Large trees in lowland evergreen rain forest for- mations on both Caribbean and Pacific slopes, 5- 500 m elevation. Flowering in January-August; fruiting in March-October. The species ranges from northern Costa Rica to Peru and Brazil.
Alchorneopsis floribunda is recognized by its tripliveined gland-tipped crenate leaves, long slen- der unbranched axillary inflorescences with dis- tant flowers or clusters of flowers, and unusual seeds. Additional characters are the longer petioles drying darker near apex and base and the occa- sional presence of pit domatia. These trees can become part of the forest canopy.
Aleurites Forster & G. Forster
Trees, monoecious, with simple or stellate hairs, sap milky; stipules paired at the node or poorly developed, caducous. Leaves alternate, simple, petioles long and with 2 glands at the apex, blades of the young treelets or early branches often with large lobes, margins entire or with minute glands or poorly developed serrations (or sinuses), venation palmate or pinnate. Inflorescences ter- minal or axillary, open-branched panicles of few-flow- ered cymes (thyrsiform), bisexual with proximal flowers mostly $ and distal or terminal flowers 9, pedicels short. Male flowers with a united calyptrate calyx splitting into 2-3 parts at anthesis, petals 5, longer than the sepals, imbricate, narrowed at the base, disk 5-lobed; stamens 5-20, from a conical receptacle in 1-4 series, outer 5 stamens opposite the petals and alternating with glan- dular lobes of the disk; pistillode absent. Female flowers with perianth similar to <? but caducous, staminodes ab- sent; ovary with 2-5 locules, ovules 1/locule, styles 2- 5, divided to near the base. Fruits drupaceous or a de- hiscent 2-5-seeded nut, usually with fleshy exocarp and bony endocarp.
A genus of six species of China, Southeast Asia, Malaysia, and the western Pacific. However, Aleu- rites has also been interpreted as a genus of only two species (cf. Webster, 1 994b, p. 1 1 4). A number of species are now grown throughout the tropics and subtropics for the seeds, which produce drying oils. Two species are commonly planted in Latin America. Larger leaves of young plants are often deeply lobed. The paired glands at the apex of the petiole, palmate venation, spatulate petals, and drupaceous fruits help distinguish the genus.
la. Puberulence of simple hairs, usually sparse; flower buds 8-12 mm long, glabrous; ovary 3-5-locular A. fordii
BURGER & HUFT: FLORA COSTARICENSIS
63
Ib. Puberulence of scurfy stellate hairs, often dense; flower buds 2-4 mm long; ovary 2-locular
. A. moluccana
Aleurites fordii Hemsl. in Hook., Icon. PI. 29:
2801-2802. 1909.
Trees to 8(-15) m tall, much branched, with smooth pale gray bark, leafy stems 3-7 mm thick, glabrous or with few thin hairs to 1 mm long, drying dark with pale lenticels ca. 1 mm long; stipules 2-4 mm long, caducous. Leaves deciduous, petioles 7-16 cm long, 1.2-4.8 mm thick, glabrous, glands 1-4 mm long, 1-3 mm broad, sessile or stalked, base of dried petiole often contracted for 3-6 mm; leaf blades 7-17(-24) cm long, 4-14(-23) cm wide, ovate or with 3 or 5 prominent lobes (sinuses to 6 cm deep), apex acuminate, margin entire to slightly undulate, base rounded and truncate to subcordate, gla- brous and deep green above, glabrous or with thin yel- lowish hairs to 1 mm long beneath, venation palmate with 3-5 major veins, 2° veins 5-8/side of the midvein. Inflorescences dichotomously branched with distal cymes, with relatively few flowers, to 12 x 18 cm, glabrous, central terminal flower 9 with the others usually <5. Flow- ers white, <5 calyx 3-5 mm long, $ calyx 8-12 mm long, petals 5-17 mm long, to 6 mm wide, spatulate, marked with pink, with many parallel veins, filaments 12-16 mm long, anthers ca. 2 mm long. Fruits 4-6 cm long, 5-7 mm diam., subglobose to ovoid, becoming dark brown, 5-locular.
Aleurites fordii originated in western China; it is found in gardens or special plantings in Central America. The seeds are the source of tung oil, a rapidly drying oil that is used for outside protec- tive paints and waterproofing. The seeds average 50% oil; residue seed cake (from oil-extracted seeds) is toxic but has been used as a fertilizer. Aleurites montana is similar and originated in the subtrop- ical areas of China and Burma; it is better adapted to the moist tropics than is A. fordii.
Aleurites moluccana (L.) Willd., Sp. PI. ed. 4: 590. 1 805. Croton moluccanum L., Sp. PI. 1005. 1 753. A. triloba J. R. Forster, Char. gen. pi. ed. 2, 112. 1776.
Trees 6-20 m tall, with spreading or pendulous branches, wood pale and weak, leafy stems 4-10 mm thick, densely covered with scurfy-stellate hairs 0.2 mm broad, becoming pale grayish; stipules ca. 5 mm long, narrowly triangular, caducous. Leaves with petioles 5- 22 cm long, 1.8-5 mm thick, glabrescent, apical adaxial glands ca. 1.3 mm wide, disk-like or shallow cups; leaf blades 1 0-23(-30) cm long, 6-1 7(-27) cm wide, narrowly to broadly ovate, ovate-triangular or with 1-2 large (2- 3 cm) lobes on each side, apex acute to subacuminate, rounded and truncated at the base, edge with minute glands in shallow (0.3 mm) sinuses, very sparsely pu- berulent above, with minute (0.2 mm) stellate hairs be- neath, venation palmate with 3 or 5 major veins (sub- palmate in smaller leaves), 2° veins 4-6/side. Inflores-
cences 6-16 cm long, to 17 cm wide, widely branching with flowers in distal cymes, densely pubescent with scurfy-stellate hairs, $ flowers many, 2 flowers few. Flow- ers densely pubescent, buds ca. 3 mm long, petals 5-6 mm long, 1.3-2.2 mm wide, obovate-oblong; stamens 1 5-20 (in <5); ovary ca. 3 mm long, ovoid, densely stellate- pubescent, styles 0.5-1 mm long. Fruits 3-6 cm diam., subglobose-oblate to ellipsoid, covered with a dense in- dumentum of appressed stellate hairs 0.1-0.2 mm wide, olive-green with whitish flesh.
Aleurites moluccana, native to south Asia and the western Pacific, is now widely cultivated in tropical regions. It is well adapted to humid trop- ical environments where A. fordii does not grow as well. Though poisonous, the seed is used for making soap and paint. The species is also used as an ornamental and shade tree, appearing whit- ish from a distance. It is called nuez and "candle- nut tree." (See fig. 324 in Correll & Correll, 1982.)
Amanoa Aublet
REFERENCE— W. J. Hayden, Notes on Neotrop- ical Amanoa (Euphorbiaceae). Brittonia 42: 260- 270. 1990.
Trees or shrubs, monoecious, glabrous, heartwood reddish to purple-brown, moderately to very dense; stip- ules intrapetiolar, united above the upper (adaxial) base of the petiole and forming an oblique-decurrent ligule- like structure, persistent. Leaves alternate, simple, short- petiolate, without glands, blades subcoriaceous and en- tire, pinnately veined. Inflorescences basically of solitary axillary fascicles or glomerules but these more often al- ternate on leafless axes that appear spicate or paniculate (with alternate lateral branches), flowers sessile and sub- tended by a loose involucre of many imbricate small bracts (the bracts larger in African species). Male flowers with 5 unequal imbricate sepals, usually larger than the small scale-like petals, disk inconspicuous, extrastam- inal, lobed; stamens 5, opposite the petals, filaments free, shorter than the anthers, anthers ovoid, dehiscing lon- gitudinally and introrse; pistillode 3-lobed distally. Fe- male flowers with 5 sepals, imbricate and subequal, pet- als small and often scale-like, disk small and 5-lobed, staminodes absent; ovary 3-locular, globose, ovules 2/locule, styles short and united, stigmas 3, thick and bifid, reflexed. Fruits woody capsules or drupe-like, sur- face muricate, endocarp usually thick, tardily dehiscent into 3 (2, 1) 2-valved cocci, columella large and per- sisting; seeds 1/locule, ovoid to ellipsoid, smooth and ecarunculate, endosperm little or none, cotyledons mas-
A small genus with 1 3 species in tropical Amer- ica and 3 in Africa-Madagascar. Only one species
64
FIELDIANA: BOTANY
is known to occur in southern Central America. The two ovules per locule place the genus in sub- family Phyllanthoideae.
Anianoa guianensis Aublet, Hist. pi. Guiane Fr. 256, t. 101. U75.A.potamophilaCroizat,AmeT. Midi. Naturalist 29: 475. 1943. A. macrocarpa Cuatrecasas, Brittonia 1 1: 164. 1959. Figure 27.
Shrubs or small trees, 2-7 m tall, leafy stems 2-6 mm thick, glabrous, brownish, often with elevated lenticels 0.5-1.5 mm long; stipules 0.7-2 mm long, broadly rounded above the adaxial petiole base, reddish brown, persisting. Leaves with petioles 4-8 mm long, 0.8-2.5 mm thick, drying dark, glabrous; leaf blades 7-14 cm long, 2.5-7 cm wide, elliptic, elliptic-oblong, oblong or obovate, gradually or abruptly narrowed to the short- acuminate apex, base obtuse to rounded or subtruncate, drying subcoriaceous and dark grayish brown, glabrous, 2° veins 7-9/side, arising at angles of 60-80°, weakly loop-connected 5-9 mm from the leaf edge. Inflores- cences of axillary fascicles or the fascicles often on a leafless terminal stem-like rachis to 16 cm long, un- branched or with 1-2 lateral branches, fascicles separated by 4-1 2 mm along the rachis, subtended by an involucre of bracts 5x8 mm, distal rachis 1.5-3 mm thick, gla- brous, bracts ca. 2 x 2 mm. Male flowers with sepals 7-9 mm long, ovate, thick, petals 0.7-1 mm long, disk 1.1-1.4 mm diam., cupulate; anthers ca. 5 mm long; pistillode ca. 5 x 2.5 mm, 3-lobed. Female flowers with sepals 7-9 mm long, ovate-oblong, petals 1.5-1.7 mm long, 2-2.3 mm wide, suborbicular, minutely denticu- late; pistil 2.5-5 x 2-2.5 mm, ovary and thick stylar column not differentiated, stigmas ca. 1.3 x 1.8 mm, sessile, obscurely 2-lobed. Fruits 2-3 cm long, 2.5-3 cm diam., subglobose, slightly compressed at base and apex, borne on a thickened pedicel 3-15 mm long, splitting into 3-6 woody parts, outer wall 3-4 mm thick, colu- mella 1 5 mm long, 7 mm wide; seeds 1 5 x 13x9 mm, cordate-triangular in outline, smooth and lustrous, scar 3x2 mm.
Plants of lowland seaside forest formations and swamp forests, 0-150 m elevation. Flowering in March and October; fruiting in February-March, October, and December. This species has been collected along the Caribbean coast of Belize, Gua- temala, and Nicaragua and in central Panama. It ranges southward to the Guianas.
Amanoa guianensis is recognized by its restric- tion to lowland forests near the seacoast, the flow- ers in sessile involucrate fascicles on inflorescences that appear to be leafless branchlets, and thick- walled woody fruits. The ovaries with two ovules per locule develop into three-seeded fruits by abor- tion. Although not yet collected in Costa Rica, it occurs in adjacent Nicaragua.
Antidesma bunius (L.) Spreng., the "Chinese laurel," is occasionally cultivated in Central America. These ornamental shrubs have un-
branched unisexual inflorescences and sweet dru- paceous fruits with solitary seeds. The 9 flowers have an annular disc and the ovary is one-locular with one broad stigma. The male flowers have two to five stamens, a small pistillode, and four to five small imbricate calyx lobes. The eglandular leaves are pinnately veined, entire, and subcoriaceous. Antidesma, a paleotropical genus of ca. 160 spe- cies, is closely related to Hyeronima.
Aparisthmium Endlicher
Trees or shrubs, dioecious, pubescence of short simple hairs; stipules 2, small, lateral. Leaves alternate, petio- late, with 2 stipel-like appendages at the apex of the petiole, blades ovate, pinnately veined, serrulate. Male inflorescences mostly terminal, paniculate, bracts sub- tending small glomerules of sessile flowers, $ flowers small, ovoid in bud, calyx splitting into 2-3 valvate sepals, petals and disk absent; stamens 4 (3, 5), filaments united at the base, separate in the distal half, anthers longitu- dinally dehiscent, connective not prolonged; pistillode absent. Female inflorescences racemose (or with a few lateral branches), bracts biglandular, subtending 1 (2) flower; 9 flowers with 4-6 sepals, petals and disk absent, staminodes absent; ovary 3-locular, ovules 1 /locule, styles 3, united at base and thick, minutely 2-lobed at the apex, papillate on interior surfaces. Fruits capsules splitting into 3 2-valved cocci, columella persistent; seeds eca- runculate, endosperm carnose, cotyledons flat, oblong.
A monotypic genus, until recently, known only from South America. The recent addition of this species to the Central American flora is another example of an Amazonian species disjunct in southwestern Costa Rica. Continued use of the generic name will need conservation (Webster, 1994b). The genus is currently being studied by Ricardo Secco (MG).
Aparisthmium cordatum (Juss.) Baill., Adansonia 5: 3-7. 1865. Conceveibum cordatum Juss., Eu- phorb. gen. 43, t. 13, f. 42a. 1824. Alchornea macrophylla Mart., Herb. fl. bras. 24 (beibl 2): 31. 1841. Figure 20.
Trees or shrubs, 3-1 0 m tall, leafy stems 4-9 mm thick, minutely puberulent with thin hairs 0.1-0.4 mm long; stipules to 3 mm long, subulate, caducous. Leaves al- ternate or congested beneath distal flowering nodes, pet- ioles 1.2-1 1(-18) cm long, 1-2.7 mm thick, minutely puberulent, with 2 stipel-like structures at the adaxial/ lateral apex, 2 flat rounded glands 1-1.5 mm diam. pres- ent at the base of the blade in the abaxial surface; leaf blades (10-)12-24(-32) cm long, 5-15(-19) cm wide, ovate-elliptic to broadly ovate or ovate-orbicular (small- er leaves narrowly ovate-elliptic), apex acuminate to cau- date-acuminate, the narrow tip 1-2.5 cm long, margin
BURGER & HUFT: FLORA COSTARICENSIS
65
crenate or serrate with rounded glandular teeth ca. 1 mm high (subentire), base rounded and truncate to subcor- date (cuneate in smaller leaves), drying stiffly charta- ceous and dark greenish, upper surfaces with minute (0. 1-0.2 mm) hairs along the major veins, lower surfaces minutely puberulent or glabrescent, 2° veins 6-1 I/side. Male inflorescences and flowers not seen. Female inflo- rescences not seen at anthesis, solitary and axillary or several from a condensed distal node, 1 6-40 cm long in fruit, bracteoles ca. 1.5 mm long, triangular, fruits borne on pedicels 10-18 m long, 0.4-0.9 mm thick, minutely puberulent. Fruits 6-8 mm long, 8-1 1 mm wide, deeply 3-lobed, sparsely puberulent with minute hairs, sub- tended by persisting triangular calyx lobes 1.5-2 mm long, persisting style branches ca. 3 mm long, 0.4-0.5 mm thick, columella 3.8-5 mm long; seeds 4.5-5.5 mm long, 3.5-4 mm diam., oblong-ellipsoid.
Plants of evergreen forest on the Pacific slope in southern Costa Rica, ca. 300 m elevation. The species is known in Central America from a single collection (Wilbur et al. 23958 DUKE) from about 12 km northeast of Quepos; fruiting in August. In South America, the species ranges from Colombia, Venezuela, and the Guianas to Bolivia.
Aparisthmium cordatum is recognized by the large ovate leaves with bluntly glandular-serrate margins, minute simple hairs on many surfaces, long racemose 9 inflorescences, capsular fruits, and seeds almost circular in cross-section. The two sti- pel-like structures at the apex of the petiole (not seen in the Costa Rican collection), two flat round- ed glands on the abaxial base of the leaf, and the subparallel 3° veins are additional distinctions. Specimens may resemble Conceveiba pleioste- mona, but Aparisthmium lacks the minute stellate hairs and has dry capsules with smaller seeds.
Argythamnia P. Browne
Shrubs, subshrubs, or small trees (herbs), annual or perennial, monoecious (rarely dioecious), stems pubes- cent with appressed slender 2-parted hairs attached at the center (T-shaped), often with purplish pigment; stip- ules paired, small, persisting. Leaves alternate, simple, short-petiolate, blades dentate or entire, venation pin- nate or palmate (tripliveined), eglandular. Inflorescences axillary, solitary, racemiform, usually bisexual with 1-3 proximal 9 and several distal 3 flowers, subsessile or short-pedicellate, each flower subtended by a small bract. Male flowers with ovoid buds, sepals 5, valvate, petals 5, imbricate but narrowed at the base and adnate to stamina! column, disk of 5 glands opposite sepals; fertile stamens 5-15 in 1-3 whorls of 5 each (consistently 10 in 2 whorls in subgenus Ditaxis), united at the base to form a column, filiform staminodes sometimes present at the apex of the column, filaments united at base, short, anthers ovate, dehiscing longitudinally and introrse; pis- tillode absent. Female flowers with 5 imbricate sepals, petals 4 or 5, imbricate, usually shorter than the sepals,
entire, staminodes absent, disk cylindrical or dissected into sometimes elongate segments, filaments or glands; ovary subsessile, 3-locular, styles 3, free or united at the base, bifid d i stall y. ovules 1/locule. Fruits often borne on reflexed pedicels, capsular, 3-lobed, separating into 3 2-valved cocci, leaving a persistent columella; seeds subglobose, ecarunculate, surface reticulate to foveolate.
A genus (in the wide sense) of ca. 80 Neotropical species. Our species has also been assigned to Di- taxis, sometimes considered a subgenus of Argy- thamnia (cf. Ingram, 1980, and Webster, 1994b).
Argythamnia guatemalensis Mull. Arg., Linnaea 34: 145. 1 865. Ditaxis guatemalensis (Mull. Arg.) Pax & K. Hoffm. Pflanzenreich 4, 147, 6: 59. 1912. Figure 11.
Herbaceous subshrubs, stems erect or horizontal, 0.5- 1 m tall, from a woody rootstock, leafy stems 0.8-2.8 mm thick, sericeous with slender whitish linear 2-branched hairs attached at the center (but difficult to see), 1-3 mm long; stipules 1-3 mm long, 0.2-0.5 mm wide at the base, linear, acute, persistent or deciduous. Leaves with petioles 0.7-3(-6) mm long, 0.5-1.5 mm thick, densely sericeous; leaf blades 17-85 mm long, 8- 35 mm wide, ovate-elliptic to ovate-lanceolate or lan- ceolate, apex acute with minute gland tip, usually cuneate at the base, margin minutely (0.2-0.5 mm) serrate with 1 2-30 teeth/side, drying chartaceous and grayish, with hairs 0.3-1 .3 long on the upper surface and shorter dense hairs beneath, 2° veins 3-4/side and strongly ascending, becoming impressed above. Inflorescences 6-1 5 mm long, subglomerulate with few flowers, peduncle 1-5 mm long, densely sericeous, flowers subsessile or short-pedicellate. Male flower buds ca. 4 mm long, sericeous, sepals 1.5— 3 mm long, petals 2-2.8 mm long; stamens 10 with 3 small staminodes, anthers orange. Female flowers with buds ca. 4 mm long, sericeous, sepals 3.5—4.5 mm long, 0.6—1.3 mm wide, narrowly oblong to oblanceolate, pet- als 1-2 mm long; ovary 2-2.5 mm long, 3-3.5 mm wide, oblate, short-pubescent, style column 0.7 mm long, style branches 0.7 mm long. Fruits 4x6 mm, oblate, short- sericeous, columella 2.2 mm high, I-shaped; seeds 2.5- 3 mm long, 2-2.5 mm wide, surface reticulate with hex- agonal depressions 0.3-0.5 mm wide.
Plants of the seasonally deciduous lowlands of northeastern Costa Rica, 0-200 m elevation. Flowering in February, April, August-October, and December. The species ranges from Mexico along the Pacific side of Central America to the Bay of Nicoya in Costa Rica.
Argythamnia guatemalensis is recognized by the unusual hairs (attached at the center but difficult to see), short few-flowered axillary inflorescences, unisexual flowers, sepals and petals differing only slightly in length in 6 flowers, herbaceous habit, and restriction to seasonally deciduous habitats. The description of this species in the Flora of Gua-
66
FIELDIANA: BOTANY
temala (Standley & Steyermark, 1 949) lists larger floral parts than those seen in Costa Rica.
Astrocasia Robinson & Millspaugh
REFERENCE— G. L. Webster, Revision of Astro- casia (Euphorbiaceae). Syst. Bot. 17: 311-323. 1992.
Small trees and shrubs, monoecious or dioecious, gla- brous; stipules lateral, ribbed with parallel venation, de- ciduous. Leaves alternate, petiolate, sometimes peltate, blades entire, pinnately veined, glabrous. Inflorescences axillary, flowers in fasciculate glomerules of few to many 6 flowers or 1-3 9 flowers, subtended by stipule-like bracts, borne on long thin glabrous pedicels. Male flowers gla- brous, sepals 5, free, usually unequal with outer smaller and thicker, imbricate in bud, petals 5, free, longer than the sepals, disk annular or patelliform; stamens 3-5, fil- aments united to form a column, anthers sessile or stip- itate on the column, 2-thecous, lateral on the flattened apex of the column, dehiscing horizontally or deflexed, pistillode sessile or stipitate on the dilated apex of the staminal column. Female flowers glabrous, sepals 5, free, imbricate in bud, deciduous, petals 5, free, larger than the sepals, staminodes absent; disk annular to cupular, entire or slightly lobed; ovary 3- (rarely 4)-locular, ovules usually 2/locule, anatropous, styles 3 or 4, short and united at the base, branches short and bifid. Fruits cap- sules, thin-walled separating into 3 (4) 2-valved cocci, columella persisting, slender; seeds 1/locule, smooth, ecarunculate, raphe conspicuous, endosperm copious, cotyledons thin, flat.
A Neotropical genus of five species ranging dis- junctly from Mexico and the West Indies to Brazil and Bolivia. The unisexual plants, lack of pubes- cence, deciduous leaves, flowers from distal stems on long thin pedicels, free petals, peltate androe- cium, cupulate 9 disk, and capsular fruits help dis- tinguish this genus. In a 9 flower we dissected, there was only one ovule per locule, with some indi- cation that the second ovules had failed to devel- op.
Astrocasia tremula (Griseb.) Webster, J. Arnold Arbor. 39: 208. 1958. Phyllanthus tremulus Gri- seb., Fl. Brit. W. Ind. 34. 1859. Astrocasia phyl- lanthoides Robins. & Millsp., Bot. Jahrb. Syst. 36, Beibl. 80: 19. 1905. Figure 32.
Small trees or shrubs 1.5-6(-10) m tall, dioecious (or monoecious), leafy stems 0.7-3 mm thick, glabrous, be- coming pale grayish with elliptic lenticels; stipules 4-9 mm long, ca. 1.5 mm wide at base, narrowly triangular, glabrous, yellowish, venation parallel, caducous. Leaves deciduous, glabrous, petioles (4-) 12-68 mm long, 0.5- 1.5 mm thick, sometimes thickened (geniculate) at apex and base, with 1 or 2 small (0.3-0.7 mm) glands/stipels
at apex adaxially (at base of mature blade); leaf blades 3.5-10(-14) cm long, 2.5-6(-9) cm wide, ovate to ovate- rhombic or ovate-elliptic, apex obtuse or acute, margins entire (slightly undulate when dried), base broadly ob- tuse, drying membranaceous (flowering material) to chartaceous, glabrous, 2° veins 3-7/side. Male inflores- cences from axillary short-shoots 2-6 mm long, fascic- ulate with 5-20 flowers, glabrous, bracts 2-3 mm long, with parallel venation, pedicels 8-18 mm long, 0.1-0.2 mm thick; $ flowers 3-4 mm wide, sepals 0.7-1.3 mm long broadly elliptic to obovate, entire, petals 1.5-3.5 mm long, oblong, disk often obscure, 0.9-1.8 mm wide; staminal column 0.3-0.4 mm long, ca. 0.2 mm thick, terminated by a peltate flat apex 0.8-1.1 mm wide, with 5 stamens represented by 1 0 thecae borne along the outer rounded periphery, anthers ca. 0.3 mm high; pistillode sessile on the staminal column. Female inflorescences of 1-5 flowers in axils of leaves or fallen leaves, glabrous, pedicels 2-5 cm long, 0.4-0.7 mm thick; 9 flowers ca. 4 mm long, glabrous, sepals 1.7-2.5 mm long, petals 3.5- 4.2 mm long, 1.3-1.7 mm wide, obovate to spatulate, rounded distally, disk forming a thin cup 0.5-1 mm high and ca. 2.2 mm ilium.; pistil ca. 2 mm long, ovary ca. 1.2 mm diam., styles ca. 0.6 mm long. Fruits 8-9 mm long, 10-12 mm wide, oblate, with 3 rounded lobes, glabrous, persisting stigmas ca. 0.4 mm long, columella 3.5-5 mm long, I-shaped; seeds 4-5 mm long, 3.3-4 mm wide, ca. 3 mm thick, irregularly rounded to wedge- shaped, smooth, uniformly yellowish or dark brown.
Plants of the evergreen Caribbean lowlands, 20- 500 m elevation. Fruiting in October-March. Known in Costa Rica only from Bajo Rodriguez (north of San Ramon), Alajuela (Gomez- Laurito 12368 usj). The species is usually found on lime- stone and ranges disjunctly from southeastern Mexico, Belize, Guatemala, Jamaica, central Pan- ama, and northern South America to eastern Bra- zil.
Astrocasia tremula is recognized by its complete lack of pubescence, usually dioecious plants, few flowers on slender pendulous pedicels arising from the stems or short-shoots, well-differentiated se- pals and petals, and unusual peltate androecium on which the thecae form a 10-lobed margin. Flowering appears to occur with the flush of new foliage. This species is closely related to A. peltata Standley of Mexico.
Bernardia Miller
Shrubs or small trees, monoecious or dioecious, pu- bescence of simple or stellate hairs; stipules small. Leaves alternate, simple, petiolate to subsessile, pinnately or palmately 3-veined, margins dentate, often with 2 glan- dular areas near the base of the blade, without stipels. Inflorescences unisexual and solitary, ,', axillary or pseu- doterminal, short or long spikes, bracts subtending 1-7 sessile or short-pedicellate flowers; 9 terminal or axillary to distal leaves, flowers aggregated (and few-flowered) or
BURGER & HUFT: FLORA COSTARICENSIS
67
sessile on spikes, each concave bract subtending 1 9 flow- er. Male flowers globose in bud, calyx splitting into 3- 5 valvate sepals, petals absent, disk usually of minute elements among stamens bases; stamens 3-30, filaments free, slender, short, anthers 2- or 4-lobed (emarginate), dehiscing longitudinally, thecae subglobose; pistillode small or none. Female flowers with 4-6 imbricate sepals (and subtended by similar bracts), petals absent, disk annular or of separate glands, staminodes absent; ovary 3-locular, ovules 1/locule, style column short, branches
2-lobed, simple to lacerate. Fruits capsular, breaking into 3 2-valved cocci, columella persisting; seeds carinate, rounded to prismatic, ecarunculate, endosperm carnose.
A tropical American genus of ca. 50 species, with the majority of species in Brazil and a second center of diversity in Mexico. Our two species are quite different in appearance and habitat.
Key to the Species of Bernardia
la. Plants of evergreen montane forest formations; leaves elliptic-oblong to lanceolate, to 20 cm long;
pubescence mostly of simple hairs B. macrophylla
Ib. Plants of deciduous forest formations of Guanacaste; leaves ovate, to 1 1 cm long, pubescence of
stems and leaves mostly of stellate hairs B. nicaraguensis
Bernardia macrophylla Standl., J. Wash. Acad. Sci. 15: 103. 1925. Figure 12.
Shrubs 1.5-3 m tall, monoecious, leafy stems 1-4 mm thick, appressed-pubescent with thin simple ascending hairs 0.2-0.5 mm long; stipules 1.2-1.9 mm long, 0.5- 1 mm broad at the base, narrowly triangular, persistent. Leaves with petioles 3-10 mm long, 0.5-1 mm thick, densely appressed-hispidulous, glands absent; leaf blades 6-16(-20) cm long, 1.5-5(-7.5) cm wide, narrowly ellip- tic-oblong to narrowly elliptic or lanceolate, tapering gradually to the acuminate apex, margin with gland- tipped serrations 0.2-0.7 mm high, 1 5-40/side, base acute and slightly decurrent on the petiole, drying chartaceous, 2° veins 7-1 1 /side, arising at 30-40°. Male inflorescences 2.5-7 cm long, often axillary to older leaves, peduncles 2-3 cm long, appressed-puberulent, 0.7 mm thick, glom- erules 1 .4-5 mm distant along the rachis, with 3-6 flow- ers, bracts ca. 1 x 2 mm, pedicels 1-1.5 mm long; $ flower buds 1.3 mm diam., sepals 1.2-1.8 mm long, 0.7- 1.1 mm wide, lanceolate, disk represented by minute clavate glands; stamens ca. 1 5, filaments 0.7-1 mm long, slender, anthers 0.2 x 0.4 mm. Female inflorescences in axils of distal leaves, 5-25 mm long, densely pubescent, peduncle ca. 2 mm long, flowers few, subtended by bracts ca. 2 mm long; 9 flowers pubescent, sepals 5, 1.6-1.8 mm long, 0.8-1.3 mm wide, ovate, disk 0.2-0.3 mm high, glabrous; ovary 1-2 mm long, style branches 0.4 mm long. Fruits ca. 7 x 8 mm, yellowish, rugulose, sparsely minutely puberulent.
Plants of evergreen forest formations; known from 1 800 m elevation in easternmost Costa Rica but collected near sea level in Panama (Standley 29389 us holotype). Flowering and fruiting in March in Costa Rica (Davidse et al. 25611 CR, MO). The species is known only from the collection cited above and a few collections in Panama.
Bernardia macrophylla is recognized by its long slender $ spikes, narrow dentate leaves, simple hairs, and unisexual flowers. Webster and Burch
(1967) describe the species as dioecious, but our material is clearly monoecious. This species should be reexamined when more material becomes available.
Bernardia nicaraguensis Standl. & L. O. Wms., Ceiba 1: 85. 1950. Figure 12.
Shrubs or small trees, 2-8 m tall, dioecious, leafy stems 1.5-4 mm thick, stellate-tomentulose with yellowish hairs 0.2-0.8 mm long, glabrescent and dark grayish in age, terete; stipules 2.5^4 mm long, 1 mm wide at the base, lanceolate, deciduous. Leaves with petioles 4-17 mm long, 0.8-1.6 mm thick, densely stellate-tomentulous; leaf blades 3-12 cm long, 2-8 cm broad, ovate to ovate- elliptic or broadly elliptic, apex obtuse to acute, margin irregularly crenate-dentate with 1 5-35 teeth/side 0.3-1 .5 mm high, base obtuse to somewhat rounded and sub- truncate, drying chartaceous and darker above, scabrous with stellate hairs ca. 0.3 mm long above, with dense stellate hairs 0.3-0.8 mm diam. beneath, 2° veins 4-67 side, subpalmate with the basal 2° veins often reaching the middle of the blade, central 2° veins arising at angles of 40-50°. Male inflorescences 12-40 mm long, 3-5 mm wide, at first erect and cone-like, bracts 2-3 mm long, broadly ovate, with dense straight hairs ca. 0.3 mm long; $ flowers with 4 sepals 2.5 x l mm, densely tomentulous on the exterior but glabrous on the inner surface; stamens ca. 20, filaments 1-1.8 mm long, filiform, glabrous, an- thers 0.3-0.4 mm long. Female inflorescences to 5 cm long with 2-5 sessile flowers, peduncle to 14 mm long, densely stellate-tomentulous, bracts ca. 1.3 mm long; 9 flowers with sepals ca. 3 x 2 mm, stiff; ovary 3-4 mm diam., globose, densely yellowish hirtellous, style branches 1.5 mm long. Fruits ca. 7.5 x 11 mm, deeply 3-lobed, densely stellate-tomentulose, walls of cocci 0.2-0.3 mm thick, columella 4-5 mm long, 2-4 mm wide; seeds 5.5- 6.5 mm long, 4.5—4.7 wide, 4.2-4.5 mm thick, ovoid- angular, grayish brown or mottled.
Plants of open savanna formations, deciduous and partly deciduous forest formations, 20-1200
68
FIELDIANA: BOTANY
m elevation (to 1400 m in Nicaragua). Flowering in January-May; fruiting in February-August. The species ranges from Honduras to northwestern Costa Rica.
Bernardia nicaraguensis is recognized by its sea- sonally very dry deciduous habitat, dense covering of slender stellate hairs, ovate denticulate leaves with subpalmate venation, and distal leaf axils with tomentulose cone-like 3 inflorescences (in early stages) or more elongate few-flowered 2 spikes. The plants may lose their leaves as flowering progresses (Haber & Zuchowski 10483).
1 5 mm long (flowers sometimes borne in small groups on leafless axillary branches to 3 cm long); <5 calyx tur- binate; 9 calyx campanulate and lobed.
Breynia disticha, native of the New Herbrides, is often planted as an ornamental bush or in hedges in tropical gardens. The reddish stems with many small variegated leaves marked with green, white, red, or pink give a colorful effect. It is called "snow bush" and "leaf flower."
Caperonia St. Hilaire
Breynia J. R. & G. Forster (nom. conserv.)
Shrubs or small trees, monoecious, distal leaf-bearing stems resembling pinnate leaves. Leaves alternate and distichous, simple, short-petiolate, blades entire, pin- nately veined, often blackening on drying. Inflorescences axillary, flowers small, solitary or few in fascicles ($), or on leafless unbranched axillary shoots, <5 pedicels slender. Male flowers with a turbinate calyx, calyx lobes 6, im- bricate and rounded, petals and disk absent; stamens 3, filaments united, anthers elongate; pistillode absent. Fe- male flowers with 6 calyx lobes, imbricate, petals and disk absent; ovary 3-locular, ovules 2/locule, styles 3, free, bifid or simple. Fruits somewhat fleshy, incom- pletely dehiscent; seeds trigonous, with fleshy outer seed coat, ecarunculate.
A genus of 10-25 variable species in eastern tropical Asia and the Pacific. The genus is closely related to Phyllanthus but differs in the ventrally invaginated seeds with fleshy exotesta and the lack of a floral disk. Varieties of one species are widely cultivated in the tropics as ornamental shrubs.
Herbs or subshrubs, annual or perennial, monoecious (in Central America), usually growing in wet places, with simple or gland-tipped hairs; stipules paired at the leaf base. Leaves alternate, simple, short-petiolate, blades usually with gland-tipped serrate margins, venation pin- nate, laminar glands absent. Inflorescences axillary, usu- ally solitary, mostly bisexual (in Central America), spi- ciform to racemiform, pedunculate with 1-5 proximal 2 flowers and 2-10 distal $ flowers, a broadly sessile stip- ule-like bract subtending each flower, <5 flowers usually pedicellate, 9 flowers sessile or short-pedicellate. Male flowers with 5 sepals, valvate or imbricate in bud, petals 5, free, often unequal, disk absent; stamens 10 in 2 su- perposed whorls of 5, filaments united near the base into a column, free distally, anthers dehiscing longitudinally; pistillode present at the apex of the staminal column, minute, cylindrical or 3-lobed. Female flowers with 4-7 unequal sepals (often 3 larger alternating with 3 smaller), united near the base, enlarging in fruit, petals narrow or reduced and sepal-like, staminodes and disk absent; ova- ry 3-locular, muricate or with broad-based subulate hairs, styles with 3-7 lobes, ovules 1/locule. Fruits capsular, 3-lobed, echinate to hispid or verrucose over the outer and distal surfaces, subtended by the persisting perianth, breaking into 3 2-valved cocci; seeds globose, ecarun- culate, raphe narrow, surfaces with a fine reticulum form- ing small areolae (foveolate), endosperm carnose, copi- ous.
Breynia disticha J. R. & G. Forst., Char. gen. pi. 146, t. 73. 1776. Phyllanthus nivosus Bull, Cat. 9. 1873; W. G. Smith, Fl. Mag. (London) n.s. t. 120. 1874. B. nivosa (W. G. Smith) Small, Bull. Torrey Bot. Club 37: 516. 1910. B. disticha for- ma nivosa (Bull) A. R.-Sm., Kew Bull. 35: 498. 1980.
Shrubs 1-2 m tall, branching often zigzag, leafy branches 0.5-1.5 mm thick, glabrous, lenticellate; stip- ules 1-2 mm long, triangular-aculeate. Leaves disti- chous, glabrous, petioles 2-5 mm long, ca. 0.7 mm thick, without glands; leaf blades 2-6 cm long, 1.5-3.5 cm wide, broadly ovate-oblong to ovate-orbicular or elliptic- oblong, apex rounded, base rounded, drying thin-char- taceous, often variegated in color, 2° veins 2-5/side. In- florescences of solitary 2 flowers on slender pedicels 4-
A genus of ca. 40 species, mostly American but with ca. 6 African species. Our species are easily recognized because of their tendency to grow in shallow water or wet depressions in open sunny sites and the distinctive serrate leaves with many straight parallel 2° veins. Both our species exhibit extraordinary variation in leaf form, varying from linear-lanceolate to ovate-elliptic. However, such variation is rarely seen within an individual plant. Our species live in the same habitats and overlap in many morphological characteristics. Neverthe- less, the characters of the key seem to separate specimens consistently. There may be hybridiza- tion between the two species represented in Cen- tral America.
BURGER & HUFT: FLORA COSTARICENSIS
69
Key to the Species of Caperonia
la. Stems and petioles lacking slender gland-tipped hairs, stems pubescent to subglabrous; stipules ovate-triangular to triangular; seed surface with areolae 0.08-0. 1 7 mm wide; leaves mostly lanceolate to linear C. castaneifolia
Ib. Stems and petioles with few to many slender gland-tipped hairs; stipules narrowly triangular to
lanceolate; seed surface with areolae 0.06-0. 1 2 mm wide; leaves ovate to linear-lanceolate
C. palustris
Caperonia castaneifolia (L.) St. Hill., Hist. PI. Re- marq. Bresil, 245. 1824. Croton castaneifolium L., S. P. 1004. 1753. Cap. paludosa Klotzsch, London J. Bot. 2: 51. 1843. Cap. panamensis Klotzsch in Seemann, Bot. voy. Herald 103. 1853. Cap. panamensis Pax & K. Hoffm., Pflan- zenreich 63 (4, 147, 7): 424. 1914. Cap. angusta Blake, J. Wash. Acad. Sci. 14: 288. 1924. Cap. stenomeres Blake, J. Wash. Acad. Sci. 14: 288. 1924. Figure 10.
Herbs 0.3-0.8 m tall, basal stems sometimes repent, larger erect stems longitudinally ridged (Equisetum-\ike), hollow and with transverse septa, leafy stems 1.5-11 mm thick, with appressed-ascending whitish hairs 0.2-0.5 mm long, glabrescent; stipules 0.7-3 (rarely to 6) mm long, 0.5-2 mm wide at the base, triangular to narrowly ovate, usually glabrous except at the tip, not becoming reflexed. Leaves with petioles 2-22 mm long, 0.5-2 mm thick, pubescent in early stages; leaf blades 3-12 cm long, 0.7-3(-6) cm wide, linear-lanceolate to ovate-elliptic (in different plants), usually gradually narrowed to an acute or acuminate apex, with 9-30 serrations/side, base slightly rounded to subtrucate, drying membranaceous to char- taceous, glabrous above and below or sparsely pubescent on the midvein beneath, 2° veins 6-15/side. Inflores- cences 2-7 cm long, spiciform, peduncles to 4 cm long, rachis appressed-hispidulous, bracts 1-2 mm long, 9 flowers 1-3, on pedicels ca. 1 mm long, $ flowers 5-10, subsessile. Male flowers white, buds ca. 1.3 mm diam., sepals 1.5-2 mm long, petals 1.2-2 mm long, 0.5-1 mm wide, obovate, equal or unequal; anthers 0.3-0.5 mm long; pistillode 0.4-0.9 mm long, cylindrical. Females flowers with 5-6 sepals, the 3 larger becoming 3—4.5 mm long in fruit, smaller sepals 1.2-1.5 mm long, glabrous or rarely with a few simple or gland-tipped hairs, petals 1 .2-3 mm long. Fruits 4-5 x 5-6 mm, oblate and 3-lobed, broad-based hairs 0.3-0.5 mm long on distal surfaces, columclla 1.5-3 mm long; seeds ca. 3 x 2.5 x 2.5 mm, subglobose, raphe the entire length of the seed and linear, areolae 0.08-0. 1 7 mm wide, surface often pale colored and with or without transverse scales.
Plants of the margins of lakes, rivers, areas of shallow water, and moist depressions, often in open sunny sites, mostly in the Pacific lowlands, 0-500 m elevation. Probably flowering and fruiting pri- marily in the wet season (collections seen are from January-February, July, and October-Novem- ber). The species ranges from Mexico to Brazil.
Caperonia castaneifolia is recognized by its open wet lower-elevation habitats, serrate leaves vari- able in form, and bisexual spikes with unisexual flowers. It is not possible to distinguish this species from its local congener without careful review of pubescence, stipules, and seeds. The use of the Linnaean epithet to include C. paludosa was dis- cussed by Webster and Huft (1988).
Caperonia palustris (L.) A St.-Hill., Hist. PI. Re- marq. Bresil, 245. 1824. Croton palustris L., Sp. PI. 1004. 1753. Caperonia palustris var. linear- ifolia Standl. & L. O. Williams, Ceiba 1: 148. 1950. Figure 10.
Herbs 0.2-1.5 m tall, older stems often slightly in- flated, hollow, leafy stems 0.4-7 mm thick, with few to many slender gland-tipped hairs 1-2.2 mm long and shorter (0.3-1 mm) thin sharp-tipped hairs; stipules 2.5- 6 mm long, 0.4-1 mm wide at base, narrowly triangular to lanceolate, usually becoming reflexed. Leaves with petioles 2-24 mm long, 0.5-2 mm thick, usually with gland-tipped hairs to 2.2 mm long; leaf blades 3-1 2(- 21) cm long, 0.8-4(-7) cm wide, linear-lanceolate to nar- rowly triangular or ovate-elliptic (rarely ovate-oblong), tapering gradually to the acute apex, margin with 1 2-42 serrations/side, base acute to rounded or subtruncate, glabrous above, appressed whitish hairs on the veins beneath, 2° veins 5-17/side, 3° veins subparallel. Inflo- rescences 1.4-9 cm long, racemiform or spicate, with 1-
4 proximal 9 flowers and several distal <5 flowers, pe- duncles 6-^45 mm long, often with a few glandular hairs, rachis hispidulous; bracts acute, 3 flowers short-pedi- cellate, 2 flowers subsessile. Male flowers white, ca. 1.8 x 2.3 mm at anthesis, sepals 1.5-3 mm long, ca. 2 mm broad at base, petals 1.5 x 0.6 mm; anthers 0.3-0.5 mm long; pistillode 0.6-0.8 mm long. Female flowers 2.5 x 3 mm in early stages, sepals 5-9 with 3-6 larger outer sepals, becoming 3-5 mm long in fruit, triangular, usu- ally with gland-tipped hairs 1-1.5 mm long, petals 1-2 mm long; style branches 5-7, 0.4-1 mm long. Fruits 3-
5 mm long, 4.5-7 mm wide, oblate and 3-lobed, broad- based subulate hairs present on the distal surfaces, ca. 0.5 mm long, gland-tipped hairs present or absent on the subtending sepals; seeds 2.8-3 mm long, ca. 2.5 mm diam., subglobose to ovoid, areolae 0.06-0. 12 mm broad, often dark and with pale narrow transverse scale-like processes.
Plants of the margins of lakes, rivers, areas of shallow water, and moist depressions, often in open
70
FIELDIANA: BOTANY
sunny sites, mostly in the Pacific lowlands, 0-800 m elevation. Flowering in August-November; fruiting in June-December. The species ranges from the southeastern United States to Argentina. Caperoniapalustris is recognized by its open wet lower-elevation habitats, variable serrate leaves often with many parallel 2° veins, and bisexual spikes with unisexual flowers. It is not possible to distinguish this species from its local congener without careful review of pubescence, stipules, and seeds. The glandular pubescence of stems is the most consistently useful marker for this species.
Caryodendron Karsten
Trees, dioecious, stems glabrous or with simple hairs; stipules lateral, caducous. Leaves alternate, petiolate, laminae simple and entire, subcoriaceous, venation pin- nate, with 2 flat rounded glands on the adaxial surface at the base. Male inflorescences terminal or axillary to distal leaves, solitary, spiciform thyrses with a thick cen- tral rachis and a few thick alternate branches, spiciform axes with subsessile groups of 2-5 $ flowers subtended by broadly sessile bracts; $ flowers with 3 calyx lobes or parts, ovate, valvate, petals absent, disk central and large, pulviniform and often pubescent; stamens 4-7, usually with a central stamen and 1 or 2 whorls of 3 exterior to the disk, filaments free, inflexed near the apex, anthers dorsifixed, dehiscence introrse and oblique, thecae un- equal, connective apiculate; pistillode absent. Female in- florescences terminal and solitary, with a thick central unbranched rachis and 0-2 short basal branches, axes spiciform (racemose), with subsessile flowers subtended by sessile bracts; 9 flowers with a thick urceolate calyx with 3 (5-6) short rounded imbricate lobes, petals 3, broadly imbricate and rounded distally; disk forming a cup with subentire margin; staminodes absent; ovary with 3 (2, 4) locules, ovules 1/locule, styles 3, very short, stigma-like and little differentiated from the ovary. Fruits capsules, thick-walled with slightly fleshy smooth sur- faces, breaking into 3 2-valved cocci; seeds more than 1 cm long, ovoid to globose, ecarunculate.
A Neotropical genus of three species, ranging as far north as western Panama (Webster & Huft, 1988). The terminal few-branched inflorescences with thick spiciform axes are unusual among our species of Euphorbiaceae.
Caryodendron angustifolium Standl., Publ. Field Columb. Mus., Hot. Ser. 4: 217. 1929.
Trees ca. 6 m tall, leafy stems 3-5 mm thick, glabrous, smooth and yellowish gray; stipules not seen, stipule scars obscure. Leaves glabrous, petioles 1 2-22(-30) mm long, 1.5-2.3 mm thick, geniculate at the apex, petioles without glands but with 2-4 flat rounded glands in the leaf surface at base of blade adaxially; leaf blades 18-33 cm long, 5-9 cm wide, narrowly elliptic-oblong to nar-
rowly or oblanceolate, apex acuminate with tip to 5 mm wide and retuse, margins entire and recurved, tapering gradually to the cuneate base, drying stiffly chartaceous, drying yellowish gray, 2° veins 5-8/side, 3° veins sub- parallel. Male inflorescences 9-23 cm long, with a longer central axis and ca. 2 proximal lateral branches, peduncle ca. 1 cm long (to first lateral branch), 2.5-4.5 mm thick, lateral branches 1.2-1.5 mm thick, rachis ca. 2 mm diam., minutely puberulent with ascending hairs 0.1-0.2 mm long, flower clusters 3-5 mm wide, sessile, bracts ca. 2 mm long, triangular and broadly sessile, flowers 3-7, closely congested, sessile; <5 flower buds ca. 2 mm long, anthers 0.4—0.5 mm long. Female inflorescences not seen [the following information from the closely similar C. orinocensis: ca. 7 cm long, simple and unbranched or with 1-3 short (15 mm) thick lateral branches near the base, rachis 3 mm thick, flowers mostly solitary; 9 flowers with a thick calyx cup ca. 5 mm long and 4 mm diam., with short (1 mm) broadly rounded distal lobes, petals 3, broadly rounded and equaling the calyx in length, glabrous but with ciliolate distal margin; pistil ca. 4 mm long, ovoid with gradually narrowed apex and minute (0.5 mm) style branches]. Fruits not seen, probably sim- ilar to C. orinocensis where subglobose-obovoid and 3.5- 4 cm diam.
Plants of lowland evergreen forest formations near the Pacific Coast of western Panama. Flow- ering in July-August (Cooper & Slater 192 F ho- lotype, us isotype). Known only from Progreso, Chiriqui, but probably also occurring in the Golfo Dulce region of Costa Rica.
Caryodendron angustifolium is recognized by its narrow oblanceolate glabrous leaves to 30 cm long, unisexual plants with terminal inflorescences hav- ing few spiciform branches, and sessile flower clus- ters. The leaf tips usually have a notch at the apex with a terminal gland-like area, and the glands at the lamina base are imbedded in the surface. This species is very similar to some collections placed under C. orinocensis Karsten of South America. The type material of C. angustifolium differs from that species in having stipule scars that are poorly developed and leaf blades narrowly cuneate at the base. More material is necessary to assess the pop- ulation variability in Panama and to contrast this with a modern interpretation of population vari- ation in C. orinocensis.
Chamaesyce S. F. Gray
REFERENCES— D. G. Burch, Two new species of Chamaesyce (Euphorbiaceae), new combinations, and a key to Caribbean members of the genus. Ann. Missouri Bot. Gard. 53: 90-99. 1966. A. Herndon, Notes on Chamaesyce (Euphorbiaceae) in Florida. Rhodora 95: 352-368. 1993.
BURGER & HUFT: FLORA COSTARICENSIS
71
Herbs or subshrubs, annuals or with woody base, pros- trate to erect, monoecious (dioecious), stems often red- dish in color, latex whitish, glabrous or with simple hairs; stipules united at the base and interpetiolar or separate, small and often lacerate, usually persisting. Leaves op- posite, simple, short-petiolate or subsessile, blades usu- ally somewhat asymmetric at the base and cuneate to subcordate, margin serrate or entire, venation palmate or subpalmate, chlorophyll-bearing cells mostly in a sheath around the veins and veinlets with colorless areas between. Inflorescences terminal or apparently axillary (terminal on reduced axillary short-shoots), made up of 1-many cyathia, often in cymose clusters or glomerules. Cyathium resembling a flower (cf. Euphorbia), the in- volucre often resembling a calyx cup or calyx tube bear- ing 5 lobes alternating with 4 (5) sessile glands, the glands simple or often with broad flat white or red petal-like appendages. Male flowers few to many within the cy- athium, each <5 flower represented by a single stipitate stamen, anthers with 2 divergent thecae. Female flower solitary in the cyathium, represented by a stipitate naked pistil (perianth represented by a rim at the apex of the stipe), ovary 3-locular, ovules 1/locule, styles 3, free or united near the base, bifid distally. Fruits usually ex- serted from the calyx-like involucre by elongation of the stipe, capsules separating into 3 2-valved cocci; seeds ovoid to oblong, 3- or 4-sided (terete) in cross-section, surface smooth, ribbed or sculpted, usually ecarunculate, embryo straight, cotyledons flat, endosperm copious.
A worldwide genus of ca. 250 species, with most of the species in the American tropics and sub- tropics. Many plant taxonomists do not accept this genus, treating it as a subgenus of Euphorbia (see discussions in Webster & Burch, 1967; Webster, 1994b, p. 129; McVaugh, 1993, p. 210). Both taxa
possess the cyathium, a flower-like structure made up of a number of reduced <3 flowers and a single 9 flower within a calyx-like involucre or floral cup. The reduced 6 and 9 flowers consist only of indi- vidual stamens or an individual pistil; they usually have no perianth (see the discussion under Eu- phorbia). Both individual stamens and pistils are pedicellate, here called stipitate to avoid confu- sion. The edge of the involucre usually has a space resulting from the failure of the 5th gland to de- velop; the 9 stipe (pedicel) often deflects in this area. As in Euphorbia, the latex of these plants may be caustic; they are not eaten by livestock or most insects. The sap is sometimes used medici- nally (cf. C. bahiensis and C. hind).
Species of Chamaesyce are usually easy to rec- ognize because of their small opposite distichous leaves that are clearly asymmetric at the base, stip- ules usually united between the petiole bases, and milky sap. Stems and leaves are often marked with red or purple. The leaves are often held in a single plane and slightly succulent. In thin leaves viewed by transmitted light, the minor veins are seen as free-ending within clear areas of the leaf. The small- leaved prostrate mat-forming species are usually called golondrina in Central America, a name that may also be used for Alternanthera polygonoides (Amaranthaceae). Chamaesyce species are almost always plants of open sunny or early secondary succession sites, often associated with sandy or gravelly soils.
Key to the Species of Chamaesyce
la. Fruits glabrous (rarely with a few hairs at the base) 2
Ib. Fruits puberulent (only on the edges in C. prostratd) 8
2a. Leaf blades entire or slightly crenate at the apex, not > 16 mm long, blades usually of similar
size on main stems and lateral stems; plants erect or prostrate 3
2b. Leaf blades serrulate along the distal margins, to 35 mm long; blades of the main stem often noticeably larger than those of lateral stems; plants rarely prostrate [seeds often dark gray
with poorly developed transverse ribs; species appearing very similar] 5
3a. Erect subshrubs to 60 cm tall; leaf blades stiff, ovate-elliptic or elliptic, to 16 mm long
[fruits 1.2-2 mm long; seeds 1.1-1.3 mm long; plants of Caribbean seashores]
C. mesembryanthemifolia
3b. Prostrate herbs; leaf blades not stiff, oblong to suborbicular, to 10(-12) mm long . . 4
4a. Fruits 2-2 .2mm long; seeds 1.2-1.6 mm long, smoothly rounded and with a longitudinal
line (raphe) down the adaxial side; plants of the Caribbean seashore . . C. bombensis
4b. Fruits 1.2-1.7 mm long; seeds 0.8-1.1 mm long, with 3-4 concave sides and lacking a
longitudinal line or ribs; mostly at edge of fresh water lagoons and in wet depressions
C. serpens
5a. (from 2b) Fruits becoming 2-2.6 mm long, ca. 3 mm wide; rarely collected plants of the sandy Caribbean seashore, 0-5 m elevation . C. bahiensis
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FIELDIANA: BOTANY
5b. Fruits 1-2 mm long, ca. 2-2.5 mm wide; plants of open weedy sites and also found near
seashores 6
6a. Fruits 0.9-1.3 mm long; columella < 1 mm long; transverse ribs on seeds often poorly denned, giving a pitted or irregular surface; inflorescences usually with leafless distal nodes;
stipules usually 1-1.5 mm long and conspicuous C. hypericifolia
6b. Fruits 1 .4-2 mm long; columella > 1 mm long; transverse ribs on the sides of the seeds usually prominent and well denned; inflorescences with narrow reduced leaves at distal
nodes; stipules usually ca. 0.5 mm long and inconspicuous 7
7a. Distal stems glabrous or with narrow lines of hairs along one side; common plants
C. hyssopifolia
7b. Distal stems usually with hairs along one side; uncommon plants C. nutans
8a. (from Ib) Plants with erect or trailing stems to 1.5 m long [internodes 1-6 cm long; leaf blades to 4 cm long; seeds 0.9-1.2 mm long, often with irregular ribs and dark gray in color; 10-1200 m
elevation] C. lasiocarpa
8b. Plants prostrate to procumbent (erect in C. hirtd), rarely > 0.4 m high or 0.5 m long 9
9a. Cyathia in capitate (leafless) glomerules on short or prominent peduncles; larger leaves 1 5-38 mm long; internodes to 5 cm long [stems branched mainly near the base, leaf blades usually ovate- elliptic and tapering to the apex; seeds 0.6-0.8 mm long, with transverse ribs; widespread weeds
to 1400 m elevation] C. hirta
9b. Cyathia not in congested pedunculate capitate glomerules, cyathia or glomerules usually subtended by leaf pairs or reduced leaves; larger leaves 5-18 mm long; internodes on distal stems rarely >
2 cm long 10
lOa. Fruits usually exserted and easily seen on short peduncles or on a stipitate base, not closely subtended by cyathium and leaves; distal leaf axils and inflorescences not obscured by thin cotton- like hairs 11
1 Ob. Fruits appearing sessile on the cyathium and closely subtended by subtending leaves, peduncle or stipe rarely visible without removal of adjacent leaves; distal leaf axils and base of inflorescences
with thin cotton-like whitish hairs 12
1 1 a. Leaves to 1 4(- 1 9) mm long, narrowed at the apex; cyathia in dense glomerules with subtending
leaves only at the base; seeds 0.7-0.9 mm long C. ophthalmica
lib. Leaves to 7 mm long, usually rounded at the apex; cyathia 1-3 on axillary short-shoots and
subtended by reduced leaves; seeds 0.8-1.1 mm long C. prostrata
12a. Fruits not fully exserted from the cyathial involucre, often splitting the involucre at maturity; petal old appendages small or obscure, equal in size; seeds 0.6-0.7 mm long [0-1200 m elevation]
C. thymifolia
1 2b. Fruits closely subtended by the cyathia and not splitting them at maturity; petaloid appendages conspicuous and unequal with 2 larger and 2 smaller on each cyathium; seeds 0.7-0.9 mm long
13
1 3a. Petaloid appendages glabrous above and puberulent beneath; seeds gray or pinkish; 0-2000 m and
usually found above 800 m elevation C. densiflora
1 3b. Petaloid appendages glabrous above and beneath; seeds gray to pink or brown; 0-200 m
. C. dioeca
Chamaesyce bahiensis (Klotzsch & Garcke) Du- gand & Burch, Ann. Missouri Bot. Card. 54: 344. 1967. Anisophyllum bahiense Klotzsch & Garcke, Monatsber. Konigl. Preuss. Akad. Wiss. Berlin 1859: 33. 1859. Euphorbia bahiense (Klotzsch & Garcke) Boiss. in DC., Prodr. 15 (2): 24. 1862.
Herbs to 0.4 m high, decumbent to erect, often many- branched, annual or perennial, internodes 8-35 mm long,
leafy stems 0.2-2.5 mm thick, glabrous or with thin curved hairs to 0.3 mm long; stipules 0.2-0.8 mm long, united, triangular to lacerate. Leaves sometimes dimorphic with those of the lateral branches considerably smaller than those on the main stems, petioles 0.5-1.5 mm long, 0.2- 0.5 mm thick, glabrous; leaf blades 6-20(-30) mm long, 4-8.5(-12) mm wide, oblong to elliptic-oblong or ob- long-obovate, apex obtuse to rounded, margin subentire to minutely (0. 1 mm) serrulate with up to 20 teeth/side, base asymmetric with one rounded side and the other more oblique, drying chartaceous, glabrous above, with few thin hairs to 0.8 mm long beneath, venation palmate
BURGER & HUFT: FLORA COSTARICENSIS
73
with 3 major veins. Inflorescences terminal, cyathia usu- ally solitary in dichasia subtended by opposite leaves or narrow bracts, peduncles 0.3-1 .5 mm long. Cyathia with involucres ca. 0.8 mm long, 0.6 mm wide at the apex, obconic or tubular, glabrous, petaloid appendages 0.2 x 0.3 mm or absent, white; ovary ca. 0.5 x 0.4 mm, ob- long, styles ca. 0.4 mm long. Fruits 2-2.6 mm long, 2- 3 mm wide, ovoid with truncated base and rounded sides, glabrous; seeds 1 .3-1 .8 mm long, 0.8-1 . 1 mm wide, oblong to broadly ellipsoid, with 4 rounded corners in cross-section, transverse ribs 1-3 but not well developed and sometimes giving an irregular surface, grayish.
Uncommon plants of sandy seashores, 0-5 m elevation. Probably flowering throughout the year. The species ranges along the Caribbean and At- lantic seashore from Nicaragua to southern Brazil.
Chamaesyce bahiensis is recognized by its small stature, seaside habitat, well-spaced leaves often differing in size on main and lateral stems, gla- brous cyathia and fruits, and gray seeds with un- usual surface. These plants are very similar to C. hyssopifolia but differ in the slightly larger fruits and restriction to seaside habitats.
Chamaesyce bombensis (Jacq.) Dugand, Caldasia 10: 190. 1968. Euphorbia bombensis Jacq., Enum. pi. syst. 22. 1760. E. ammannioides H.B.K., Nov. gen. sp. 2: 55. 1817. C. amman- nioides (H.B.K.) Small, Fl. Southeastern U.S. 709, 1333. 1903. Figure 6.
Herbs, prostrate or decumbent, forming loose mats to 0.8 m diam. (not rooting at nodes), leafy stems 0.3-2.2 mm thick, internodes 5-35 mm long, glabrous, often reddish; stipules 0.3-1.7 mm long, with a basal trans- verse ridge and 2-7 linear laciniate segments. Leaves often clustered distally, petioles 0.5-1.5 mm long, ca. 0.3 mm thick, glabrous; leaf blades 3-10(-12) mm long, 1 .2-5(-6) mm wide, oblong, apex obtuse or rounded and often with a mucronate tip ca. 0.2 mm long, margin entire, base slightly subcordate, asymmetric with 1 side more rounded than the other, drying chartaceous, often dark in color, glabrous, surface often reticulate, venation pinnate, 2° veins 3-6/side. Inflorescences terminal, of solitary cyathia or dichasia of condensed shoots, gla- brous, peduncles to 1 .5 mm long; cyathia with involucres 1-1.4 mm long, 0.8-1.2 mm wide distally, obconic, gla- brous, glands suborbicular, petaloid appendages ca. 0.5 mm long or absent, white; ovary 0.5-0.8 mm long, styles ca. 0.4 mm long, stipe to 2.3 mm long in fruit. Fruits 1.7-2.2 mm long, 2.2-3 mm wide, ovoid-triangular with truncated base and rounded sides, glabrous, columella ca. 1.5 mm long; seeds 1.2-1.4(-1.8) mm long, 1-1.3 mm wide, ovoid-subglobose, rounded in cross-section and 3-angled only near the apex, whitish, smooth with a longitudinal line (raphe) on the inner face.
Plants of open sunny sites along the Caribbean seashore, 0-20 m elevation. Probably flowering
throughout the year. The species ranges from Flor- ida, Cuba, and Mexico through Central America to northern South America.
Chamaesyce bombensis is recognized by its small leaves, lack of pubescence, laciniate stipules, and unusual rounded seeds. This is our only species of Chamaesyce with seeds having a longitudinal line (raphe) clearly demarked on a smooth rounded surface. The thick little leaves with reticulated (dried) surface and pinnate venation are distinc- tive.
Chamaesyce densiflora (Klotzsch & Garcke) Millsp., Publ. Field Columb. Mus. Nat. Hist., Bot. Ser. 2: 391. 1914. Anisophyllum densiflo- rum Klotzsch & Garcke, Monatsber. Konigl. Preuss. Akad. Wiss. Berlin 1859: 28. 1860. Eu- phorbia densiflora (Klotzsch & Garcke) Klotzsch in Peters, Reise Mossamb. 94. 1862. Figure 7.
Herbs to 0.6 m wide, prostrate, decumbent or erect, much branched, internodes 3-15(-30) mm long, leafy stems 0.4—2 mm thick, usually densely pubescent with thin multicellular hairs to 1 mm long, pubescent throughout, on 1 side, or in 2 longitudinal rows; stipules subulate, bifid or lacerate, slender teeth l-1.8(-2.5) mm long. Leaves subsessile or with petioles to 1 mm long, ca. 0.4 mm thick, glabrous or puberulent; leaf blades (4-)7-16(-20) mm long, 1.5-6(-9) mm wide, oblong, to ovate-oblong, apex bluntly obtuse or asymmetrically rounded, margin serrulate with small (0.1-0.3 mm) ser- rations to 16/side, base strongly asymmetric with a rounded subcordate-auriculate side and a slightly round- ed side, drying chartaceous, subglabrous or puberulent on both surfaces with thin whitish hairs ca. 0.3 mm long, venation palmate with 3 major veins, 2° veins obscure. Inflorescences terminal or apparently axillary (terminal on axillary short-shoots), 6-12 mm long, cyathia densely crowded and obscured by leafy bracts, with thin whitish hairs to 1 mm long; cyathia with involucres ca. 1 mm long, campanulate, glands suborbicular to reniform, pet- aloid appendages 0.9-1.5 mm long, 0.7-2 mm wide, of 2 unequal pairs, ovate to reniform, usually reddish (white), pilose on the lower surface; stamens with anthers 0.3 mm wide; ovary ca. 1 x l mm, densely appressed pu-