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Full text of "Flora Costaricensis"

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 



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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 340, 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 1540; 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 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 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 34 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 1245 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 04 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, 1.41.6 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, 1400 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, 2345 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 440 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 04 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 410 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 3.74.2 mm long, ca. 3 mm diam., ovoid-ellipsoid, 
smooth, brown. 

Known only from primary evergreen forest at 
Estacion Cacao (1055'38"N,8529'38"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 44.5 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 1.44 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 412 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 (8328'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- 



60 



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 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 3.54.5 mm long, 
0.61.3 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 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, 4.54.7 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 34.5 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 0.40.5 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 



72 



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 0.42 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- 
berulent, styles ca. 1.5 mm long, united for 0.5 mm, bifid 
distally. Fruits 1-1.6 mm long, 0.9-1.2 m wide, ovoid 
with truncated base, minutely pilose, columella 0.6-0.7 
mm long; seeds 0.6-0.9 mm long, 0.4-0.6 mm wide, 
oblong-triangular, 4-angled in cross-section, with 4-5 
prominent transverse ribs on each side, pale grayish or 
pink. 

Common weedy plants of open sunny sites in 
both evergreen and deciduous areas, sea level to 
2000 m elevation. In Costa Rica the species is 
most often found above 800 m elevation. Flow- 
ering and fruiting primarily in July-February. The 
species ranges from northern Mexico to northern 
South America. 



74 



FIELDIANA: BOTANY 



Chamaesyce densiflora is recognized by the usu- 
ally prostrate mat-forming habit, small closely set 
leaves strongly asymmetric at the base, and cy- 
athia densely crowded (and obscure) within hairy 
bracts in the small dense inflorescences. The larg- 
er, usually red, petaloid appendages of the glands 
occur in 2 unequal pairs on the cyathium. This is 
one of the species often called golondrina. This 
species is closely related to C. dioeca and is very 
similar in overall appearance (q.v.). 

Chamaesyce dioeca (H.B.K.) Millsp. (as C. dioicd), 
Publ. Field Columb. Mus. Nat. Hist., Bot. Ser. 
2: 384. 1914. Euphorbia dioeca H.B.K., Nov. 
gen. sp. 2: 53. 1817. Figure 6. 

Herbs, prostrate or decumbent, with many branches 
from the base and often forming flat mats, 15-70 cm 
wide, leafy stems 0.3-1 mm thick, internodes 2-18 mm 
long, puberulent with thin hairs 0.2-0.5 mm long; stip- 
ules 0.5-2 mm long, with 2-5 linear teeth. Leaves often 
marked with red, petioles 0.5-1 .5 long, 0.2-0.4 mm thick, 
glabrous or puberulent; leaf blades 3-15 mm long, 1.5- 
7 mm wide, broadly oblong to ovate-oblong or obovate- 
oblong, apex rounded to obtuse or acute, margin serrate 
with 3-6 teeth/side, base strongly asymmetric with a 
rounded to auriculate side and a cuneate or slightly 
rounded side, drying stiffly chartaceous, green or with 
purple spots, glabrous or sparsely puberulent, venation 
subpalmate with 3 major veins. Inflorescences terminal 
(often on axillary short-shoots) and tightly congested 
within the distal leaves, white pubescent at the base, 
peduncles short and rarely visible; cyathia with invo- 
lucres 0.8-1.2 long, ca. 0.7 mm diam., obconic, ap- 
pressed-puberulent, glands reniform to narrowly elliptic, 
petaloid appendages of 2 unequal pairs, reddish to white, 
glabrous on both sides, the larger 1-1.5 mm long, 1.3- 
2 mm wide; ovary ca. 0.7 mm long, styles 0.8-1 mm 
long, united for ca. 0.5 mm. Fruits 1-1.4 mm long, 1- 
1.3 mm wide, ovoid with truncated base, puberulent, 
columella 0.8-1 mm long; seeds 0.6-0.9 mm long, 0.3- 
0.5 mm wide, oblong with narrowed tip, 4-sided in cross- 
section, often with (2-)3-5 transverse ribs separated by 
pits, pinkish or brown. 

Common plants of open sunny sites in the Pa- 
cific lowlands and along the seashore, 0-600 m 
elevation (rarely to 1 200 m elevation elsewhere). 
Probably flowering mostly in the wet season (June- 
October). The species ranges from central Mexico 
to South America. 

Chamaesyce dioeca (also labeled dioicd) is rec- 
ognized by its usually prostrate habit, puberulent 
stems, stipules with two to five slender teeth, very 
small leaves, densely congested inflorescences with 
thin white hairs, subsessile puberulent fruits, and 
restriction to the Pacific lowlands. The cyathia are 
noteworthy in having conspicuous petaloid ap- 
pendages in two pairs differing in size. These ap- 



pendages are glabrous on both surfaces in contrast 
to those of the closely related C. densiflora where 
the appendages are puberulent beneath. Compare 
also the very similar C. thymifolia; see the dis- 
cussion by McVaugh (1993, pp. 214-216). We at- 
tempt to maintain a traditional usage and are not 
convinced that small differences in ribbing of the 
lateral seed surfaces is significant. 

Chamaesyce hirta (L.) Millsp., Publ. Field Co- 
lumb. Mus., Bot. Ser. 2: 303. 1909. Euphorbia 
hirta L., Sp. PI. 454. 1 753. E. globulifera H.B.K., 
Nov. gen. sp. 2: 56. 1817. Figure 7. 

Herbs 0.1-0.4 m tall, decumbent or erect, internodes 
0.5-5 cm long, leafy stems 0.4-2.5 mm thick, minutely 
(0.1 mm) puberulent to densely hirtellous with multi- 
cellular hairs to 1.5 mm long; stipules united for ca. 0.5 
mm at the base and with lobes or teeth 1-2 mm long. 
Leaves often marked with red, petioles 1 .2-3.5 mm long, 
0.3-0.7 mm thick, puberulent; leaf blades (4-)7-35(-50) 
mm long, (3-)4-14(-18) mm wide, ovate-rhombic to 
ovate-elliptic or asymmetrically lanceolate, apex acute 
to bluntly acute, margin subserrate or serrate with 6-30 
teeth/side, 0.1-0.3 mm high, base usually asymmetric 
with a cuneatd side and opposing rounded-truncate side, 
drying chartaceous, slightly rough or scabrous above with 
stiff hairs 0. 1-0.2 mm long, with longer (to 0.9 mm) thin 
hairs beneath, venation palmate with 3 (4) major veins, 
asymmetric, 2 veins 1-3/side of the midvein. Inflores- 
cences usually axillary, solitary and I/node, 4-18 mm 
long, 5-16 mm wide, peduncle 2-9 mm long, 0.4-0.5 
mm thick, puberulent, bifid distally, pedicels ca. 0.5 mm 
long; cyathia with involucres ca. 1 x 0.8 mm, obconic, 
glabrous to strigose, often reddish, glands minute, or- 
bicular, petaloid appendages usually absent; anthers ca. 
0.1 x 0.2 mm. Fruits 0.7-1. 2 mm long, 1-1.4 mm wide, 
ovate with truncated base, strigose, persisting styles 0.2- 
0.4 mm long, borne on a stipe 0.5-1 mm long, columella 
0.7-0.8 mm long; seeds 0.6-0.8 mm long, 0.4-0.5 mm 
wide, narrowly ovoid, 4-sided in cross-section, with 4- 
5 transverse ribs on each side, grayish to reddish brown 
or tan. 

Common weedy plants of open sunny sites in 
both wet evergreen and seasonally dry deciduous 
formations, 0-1400 m elevation. Probably flow- 
ering and fruiting throughout the year (but not 
collected in September-October). This species, now 
a pantropical weed, ranges from the southern 
United States to Argentina and the West Indies; 
it has been collected on Cocos Island. 

Chamaescyce hirta is recognized by its longer 
multicellular hairs, leaves usually acute at the apex, 
compact pedunculate inflorescences (usually ax- 
illary and one per node), and puberulent fruits. 
The peduncles are often short and difficult to see. 
These plants are often called golondrina in Costa 
Rica. It has been reported that C. hirta can cause 



BURGER & HUFT: FLORA COSTARICENSIS 



75 



ulcerations by the transfer of flagellates, but this 
is doubtful since the sap is often used to heal 
wounds (Standley & Steyermark, 1949, p. 105). 



sopifolia L., Syst. Nat. ed. 10, 1048. 1759. E. 
brasiliensis Lam., Encyc. Meth. Bot. 2: 423. 1 788. 
Figure 7. 



Chamaesyce hypericifolia (L.) Millsp., Publ. Field 
Columb. Mus., Bot. Ser. 2: 302. 1909. Euphor- 
bia hypericifolia L., Sp. PI. 454. 1753. C. glomi- 
fera Millsp., Publ. Field Columb. Mus., Bot. Ser. 
2: 377. 1913. E. glomifera (Millsp.) Wheeler, 
Contr. Gray Herb. 127: 78. 1939. 

Herbs 0.2-0.8 m high, prostrate or erect, usually few- 
branched with internodes 1-7 cm long, reddish or green, 
leafy stems 0.3-2.7 mm thick, glabrous or with few mi- 
nute (0. 1-0.3 mm) thin hairs; stipules 0.5-1.5 mm long, 
united and triangular or divided; leaf blades (5-)8-38 
mm long, (2-)3-16 mm wide, oblong to ovate-oblong or 
narrowly oblong, apex bluntly obtuse or rounded, margin 
slightly serrate with 7-15 teeth/side, base asymmetric 
with a slightly rounded-cuneate side and rounded-trun- 
cate side (rarely subcordate), drying membranaceous, 
glabrous, venation palmate with 3 major veins, slightly 
asymmetric, 2 veins 1-3/side of the midvein. Inflores- 
cences axillary or terminal, borne on monopodial or di- 
chotomous branches with nodes usually lacking reduced 
leaves, cyathia often crowded in short (6 mm) groups, 
glabrous; cyathia with involucres ca. 0.8 mm long, ob- 
conic, glands elliptic to suborbicular, petaloid append- 
ages white to pink (or absent); ovary glabrous, green, 
styles 0.3-0.4 mm long. Fruits 0.9-1.3 mm long, ca. 1.5 
mm wide, ovoid with truncated base, glabrous, borne 
on a stipe 0.5-1 mm long, persisting styles 0.4-0.7 mm 
long, columella 0.7-0.9 mm long; seeds 0.8-1 mm long, 
ca. 0.6 mm wide, ovoid, 4-sided in cross-section, with 
irregular depressions on the surfaces, dark gray to brown 
or yellowish. 

Plants of open sunny sites in both evergreen and 
deciduous vegetation, 0-500 m elevation. This 
species is rarely collected in southern Central 
America. Probably flowering and fruiting through- 
out the year. This species ranges from the southern 
United States, West Indies, and Mexico to Argen- 
tina and is an adventive in the Old World. 

Chamaesyce hypericifolia is recognized by its 
usually glabrous parts, usually oblong subsessile 
leaves separated by conspicuous internodes, irreg- 
ularly arranged distal cyathia lacking reduced leaves 
distally, the small fruits, and small seeds with ir- 
regular depressions on the surfaces. The distinc- 
tions between this species and C. hyssopifolia are 
subtle; fruiting material is necessary to distinguish 
them. Much Central American material deter- 
mined as this species is actually C. hyssopifolia 
(q.v.). 

Chamaesyce hyssopifolia (L.) Small, Bull. New 
York Bot. Gard. 3: 429. 1905. Euphorbia hys- 



Herbs 0.3-0.6(-1) m tall, spreading or erect, inter- 
nodes of the main sterns 1-3 cm long, leafy stems 0.2- 
3.5 mm thick, glabrous or with few minute (0.1 -0.3 mm) 
thin whitish hairs along longitudinal lines, terete; stipules 
0.3-1 mm long, triangular, divided or with an erose mar- 
gin. Leaves with petioles 0.4-3 mm long, 0.1-0.4 mm 
thick, glabrous or with a few thin whitish hairs to 0.3 
mm long; leaf blades 6-28(-35) mm long, 3-10(-l 6) mm 
wide, oblong to elliptic-oblong or oblong-obovate, apex 
bluntly obtuse or rounded, margin subentire or minutely 
(0.1-0.2 mm) serrate with 6-20 teeth/side, base usually 
asymmetric with a cuneate (slightly rounded) side and 
an opposite more rounded or truncated side, drying 
membranaceous or thinly chartaceous, glabrous, vena- 
tion palmate and slightly asymmetric, with 3 major veins, 
2 veins 3-5/side of the midvein. Inflorescences terminal 
or pseudoaxillary, monochasia or dichasia, peduncles 
0.5-2 mm long, distal nodes usually subtended by re- 
duced narrow leaves; cyathia with involucres 1-2 mm 
long, glabrous, glands oblong to reniform, petaloid ap- 
pedanges 0. 1-0.3 mm long and 0.3-0.6 mm wide, round- 
ed distally, white or pink; anthers ca. 0.1 x 0.4 mm, 
ovary 0.5-0.6 mm long, glabrous, styles 0.3-0.6 mm 
long, separate to the base. Fruits 1.5-2 mm long, 1.8-2 
mm wide, ovoid or ovoid-trigonous with a truncated 
base, glabrous, yellowish, columella 1.1-1.5 mm long, 
widened at the apex; seeds 0.8-1.3 mm long, 0.6-0.7 
mm wide, oblong or ovoid, 3- or 4-sided in cross-section, 
grayish, with 2-4 prominent transverse ribs or obscurely 
pitted, gray to black. 



Common plants of open sunny sites in evergreen 
or deciduous forest areas, 0-1100 m elevation. 
Flowering and fruiting throughout the year (prob- 
ably primarily in the wet season in deciduous for- 
mations). These plants are most often found below 
300 m elevation in Costa Rica. This species ranges 
from the southern United States and West Indies 
to Argentina; it has become naturalized in the Old 
World tropics. 

Chamaesyce hyssopifolia is recognized by its 
stems with longer internodes, oblong usually gla- 
brous leaves with palmate venation, glabrous ova- 
ries and fruits, and grayish ribbed fruits. The in- 
florescences usually bear narrow reduced leaves at 
most distal nodes. Large individuals of this species 
may resemble C. lasiocarpa, but that species has 
puberulent fruits and consistently erect habit. Cen- 
tral American material of C. hyssopifolia has often 
been misidentified as C. hypericifolia or the rarely 
collected seaside C. bahiensis; compare C. nutans. 
These plants have been used as a kidney medicine 
in Costa Rica (Stevens 24163). 



76 



FIELDIANA: BOTANY 



Chamaesyce lasiocarpa (Klotzsch) Arthur, Tor- 
reya 11: 260. 1911. Euphorbia lasiocarpa 
Klotzsch, Nov. Act. Leop. 19, suppl. 1: 414. 
1 843. E. hypericifolia L. sensu Wheeler in Contr. 
Gray Herb. 127: 73. 1939, and Fieldiana Hot. 
24, pt. 6: 105. 1944. Figure 7. 

Herbs or subshrubs with woody base and erect or 
spreading stems, 0.3-1.5 m tall, internodes 0.6-6 cm 
long, leafy stems 0.3-3 mm thick, minutely puberulent 
with thin curved hairs 0.1-0.3 mm long, glabrescent, 
terete; stipules 0.4-1.5 mm long, acute or erose. Leaves 
with petioles 0.7-3 mm long, 0.2-0.4 mm thick, puber- 
ulent with thin whitish hairs; leaf blades 7-37 mm long, 
2-16 mm wide, oblong, oblong-ovate to ovate-elliptic 
or oblong-obovoid, apex bluntly obtuse or rounded 
(acute), margin minutely serrate with 6-28 teeth/side, 
teeth 0.1-0.3 mm high, base usually asymmetric with a 
cuneate side and rounded side, drying thinly chartaceous, 
puberulent with thin whitish hairs 0.2-0.6 mm long on 
both surfaces (glabrate), venation palmate and asym- 
metric with 3 major veins, 2 veins 2-5/side of the mid- 
vein. Inflorescences of terminal or axillary cyathia in 
short-stalked leafy dichasia, peduncles 0.5-4 mm long; 
cyathia with involucres 1.2-2.4 mm long, obconic, ca. 
2 mm wide at apex, tomentulose, glands suborbicular, 
with 3-4 petaloid gland appendages 0.3-0.7 mm long, 
0.5-1.4 mm wide, white turning pink; anthers ca. 0.1- 
0.3 mm long, rounded; ovary ca. 0.7 x 0.5 mm, ovoid, 
densely whitish pubescent, styles 0.5-0.6 mm long. Fruits 
1-2.2 mm long, 1-2.2 mm wide, ovoid and 3-lobed, 
puberulent, styles 0.5-1 mm long, columella 1-1.3 mm 
long; seeds 0.9-1.2 mm long, 0.5-0.7 mm wide, oblong- 
ovoid, 4-sided in cross-section, dark reddish brown or 
dark grayish, with transverse ribs or with irregular ribs 
and a surface with depressions. 



Common plants of open sunny sites of season- 
ally dry deciduous and partly deciduous vegeta- 
tion, 10-1200 m elevation. Probably flowering and 
fruiting throughout the year (a majority of collec- 
tions were made in July-January). The species 
ranges from southern Florida, eastern Mexico, and 
the West Indies to Peru and Brazil. 

Chamaesyce lasiocarpa is recognized by its usu- 
ally erect stems, longer glabrescent internodes, short 
pubescence, oblong leaves serrate along most of 
their margins, puberulent fruits, and dark grayish 
or brown four-angled ribbed seeds. Unlike many 
of its congeners, this species is not found along 
seashores. Smaller specimens may resemble ma- 
terial of C. hyssopifolia (but that species has gla- 
brous fruits). 



Chamaesyce mesembryanthemifolia (Jacq.) Du- 
gand, Phytologia 13: 385. 1966. Euphorbia me- 
sembrianthemifolia Jacq., Enum. syst. pi. 22. 
1760. E. buxifolia Lam., Encyc. Meth. Bot. 2: 



421. 1788. E. litoralis H.B.K., Nov. gen. sp. 2: 

54. 1817. E.flexuosus H.B.K., Nov. gen. sp. 2: 

55. 1817. C. buxifolia (Lam.) Small, Fl. South- 
eastern U.S. 712, 1333. 1903. Figure 7. 

Small shrubs or subshrubs 0.2-0.6 m tall, stems erect 
or ascending, perennial with woody stems to 8 mm thick, 
usually reddish, internodes usually short (3-12 mm) and 
uniform on distal stems, leafy stems 0.6-2 mm thick, 
glabrous, nodes often thickened; stipules 1-2 mm long, 
ca. 1.5 mm broad at the base, triangular to ovate, with 
erose margin. Leaves often in 2 ranks, subsessile with 
petioles 0.3-0.9 mm long, ca. 0.3 mm thick, glabrous; 
leaf blades 5-16 mm long, 3-8 mm wide, elliptic-oblong 
to oblong-obovate, apex obtuse or acute, margin entire 
and often revolute when dried, base slightly asymmetric 
and auriculate on both sides, drying stiffly chartaceous 
and gray or yellowish, glabrous, venation palmate with 
3 major veins. Inflorescences terminal, of solitary cy- 
athia enclosed and hidden by crowded distal leaves. Cy- 
athia with involucres 1.3-1.7 mm long, 0.8-1.2 mm 
wide at apex, obconic, glabrous, glands elliptic, petaloid 
appendages 0.4-0.8 mm long, ca. 0.7 mm wide, obovate, 
white, with entire margin; ovary ca. 1 mm long, glabrous, 
styles ca. 0.4 mm long, stipe 0.5-1.2 mm long and be- 
coming 2.3 mm long in fruit. Fruits 1.7-2 mm long, 2- 
2.7 mm wide, broadly ovoid with truncated base to 
subglobose, glabrous , columella ca. 1.8 mm long; seeds 
1.1-1.3 mm long, 1-1.2 mm thick, ovoid-ellipsoid with 
rounded surfaces, the 4 longitudinal edges not well de- 
veloped except at the apex, surfaces smooth or slightly 
pitted, pale grayish. 

Uncommon plants of sandy dunes and ocean 
shores of the Caribbean, 0-20 m elevation. This 
species has not been collected in Costa Rica but 
is known from nearby Nicaragua and Panama. 
The species ranges around the shores of the Ca- 
ribbean from eastern Mexico, Florida, and the West 
Indies to northern South America. 

Chamaesyce mesembryanthemifolia is recog- 
nized by its short shrubby habit, restriction to Ca- 
ribbean seaside habitats, stiff short petiolate entire 
leaves often borne in two distichous ranks along 
the stems, conspicuous "petals," and unusual seeds. 
The seeds differ from most of our species in their 
form and smooth surface. 



Chamaesyce nutans (Lag.) Small, Fl. Southeastern 
U.S. 712, 1333. 1903. Euphorbia nutans Lag., 
Gen. sp. pi. 17. 1816. Figure 7. 

Herbs or herbaceous subshrubs to 0.6 m tall, leafy 
stems 0.4-2 mm thick, internodes 4-20 mm long, gla- 
brous or minutely (0.1 mm) puberulent along 1 side; 
stipules 0.3-1 mm long, triangular to rounded-erose or 
ciliate, translucent. Leaves subsessile, petioles 0.4-1.3 
mm long, 0.2-0.4 mm thick, glabrous; leaf blades 5-22(- 
30) mm long, 3-9(-15) mm wide, broadly oblong to 



BURGER & HUFT: FLORA COSTARICENSIS 



77 



narrowly oblong or ovate-oblong, apex obtuse, distal 
margin with 5-20 minute teeth, base asymmetric with 

2 rounded sides, drying thin-chartaceous, glabrous or 
sparsely puberulent beneath, venation palmate with 3 
major veins. Inflorescences usually terminal, solitary at 
a branch dichotomy or subtended by narrow leaves ca. 
6x2 mm, glabrous; cyathia 0.5-1 mm long, 0.5-0.7 
mm wide at apex, obconic or tubular, glabrous, glands 
elliptic, petaloid appendages present or absent, white to 
pink; ovary ca. 0.8 x 0.7 mm, styles 0.4-0.5 mm long. 
Fruits ( 1 .3-) 1 .9-2 mm long, ( 1 .4-)2-2.5 mm wide, ovoid- 
triangular with rounded sides, glabrous, borne on stipes 
to 2 mm long, columella 1.1-1.4 mm long; seeds 1-1.3 
mm long, 0.6-1 mm wide, ovoid with narrowed apex, 
rounded with 3 or 4 sides in cross-section, transverse 
ribs irregular and giving a wrinkled or pitted surface, 
dark. 

Uncommon plants of open sunny sites in both 
evergreen and deciduous forest areas, 0-500 m 
elevation. Probably flowering throughout the year. 
It is rarely collected in Costa Rica. The species 
ranges from southern Canada, the eastern United 
States, and Mexico to Costa Rica. 

Chamaesyce nutans is recognized by its erect or 
decumbent stems (often puberulent along one side), 
mostly glabrous parts, larger leaves on main stems, 
and dark seeds with irregular (apparently pitted) 
surfaces. The senior author believes that Central 
American specimens placed here are not specifi- 
cally distinct from those identified as C. hyssopi- 
folia and that C. nutans may not be worthy of 
specific rank. 

Chamaesyce ophthalmica (Pers.) Burch, Ann. Mis- 
souri Bot. Gard. 53: 98. 1966. Euphorbia 
ophthalmica Pers., Syn. PI. 2: 13. 1807. E. pro- 
cumbens DC., Cat. PL Hort. Monsp. 111. 1813. 
Figure 6. 

Herbs, prostrate or decumbent, stems 5-50 cm long, 
leafy stems 0.3-1 .8 mm thick, internodes 5-20 mm long, 
puberulent with thin straight or crooked hairs 0.2-0.8 
mm long; stipules 0.3-2 mm long, laciniate or with 2 
linear lobes, puberulent. Leaves with petioles 0.7-2 mm 
long, 0.2-0.3 mm thick, puberulent; leaf blades 3.5-14(- 
19) mm long, 2-8(-12) mm wide, ovate-elliptic to nar- 
rowly ovate-oblong or oblong, apex obtuse to bluntly 
acute, margin serrate with 6-18 teeth/side, 0.1-0.3 mm 
high and most prominent distally, base strongly asym- 
metric with a rounded side and a cuneate side, drying 
membranaceous, glabrous or sparsely to densely puber- 
ulent with hairs 0. 1-0.5 mm long, venation palmate with 

3 major veins. Inflorescences terminal, to 5 mm long, 
of congested cyathia and distal leaves, peduncles ca. 0.5 
mm long; cyathia puberulent, glands suborbicular, pet- 
aloid appendages usually absent; ovary borne on a short 
(0.5 mm) stipe, styles ca. 0.2 mm long. Fruits 1.1-1.4 
mm long, 1-1.3 mm wide, ovoid-triangular with trun- 
cated base and slightly rounded sides, surfaces puberu- 
lent with minute (0. 1 mm) whitish hairs, columella 0.8- 



1 mm long; seeds 0.7-0.9 mm long, 0.3-0.4 mm wide, 
oblong with narrowed apex, 4-sided in cross-section, 
concave or with 2-5 transverse ribs on each side, pale 
brown to grayish brown. 

Uncommon plants of open sunny sites in sandy 
river margins and weedy sites, 20-1200 m ele- 
vation. Probably capable of flowering throughout 
the year. Known in Costa Rica from a single col- 
lection made in the city of San Jose in April (Lies- 
ner 14176). The species ranges from southern 
Florida and the West Indies to Argentina and oc- 
curs in the Old World tropics. 

Chamaesyce ophthalmica is recognized by its 
congested inflorescences, very short styles, and pu- 
berulent fruit. 



Chamaesyce prostrata (Aiton) Small, Fl. South- 
eastern U.S. 713, 1333. 1903. Euphorbia pros- 
trata Aiton, Hort. kew. 2: 139. 1789. Figure 6. 

Herbs 5-20(-30) cm long, prostrate or scandent, in- 
ternodes 1-10 mm long, leafy stems 0.3-1 mm thick, 
glabrous or minutely puberulent with thin hairs 0.1-0.4 
mm long, often in 2 longitudinal lines; stipules 0.2-0.5 
mm long, erose or 2-lobed, puberulent. Leaves with pet- 
ioles 0.3-0.9 mm long, ca. 0.2 mm thick, glabrous or 
puberulent; leaf blades 2-9 mm long, 1-5 mm wide, 
oblong to oblong-obovate or oblong-ovate, apex round- 
ed or bluntly obtuse, margin minutely denticulate dis- 
tally with 3-9 minute teeth/side, base slightly asym- 
metric with larger rounded side and a shorter somewhat 
cuneate side, drying chartaceous, glabrous, venation pal- 
mate with 3 major veins. Inflorescences axillary or ter- 
minal on small axillary short-shoots with reduced (2 
mm) leaves, 2-8 mm long, cyathia 1-3, peduncles 0.5- 
2 mm long, to 2.3 mm in fruit; cyathia with involucres 
0.6-0.9 mm long, 0.4-0.6 mm wide at the apex, obconic, 
glabrous or sparsely puberulent, glands suborbicular, 
petaloid appendages 4, very small, as wide as the glands. 
Fruits 1-1.5 mm long, 1.2-1.4 mm wide, ovoid with 
truncated base, often with hairs along the 3 longitudinal 
edges and glabrous on the flattened surfaces, borne on a 
stipe 0.7-1. 7 mm long, columella 0.9-1. 3 mm long; seeds 
0.8-1.1 mm long, 0.4-0.5 mm wide, ovoid-oblong, 
sharply tetragonous in cross-section, gray, tan, or pink- 
ish, sulcate or with 4-6 narrow transverse ribs on each 
side. 



Plants of open sunny sites, 0-1200 m elevation. 
Probably flowering throughout the year in Central 
America. (In Costa Rica, collected only in March- 
April, in and near San Jose.) The species ranges 
from the southern United States (Texas-Florida), 
Mexico, and the West Indies to northern South 
America. 

Chamaesyce prostrata is recognized by its usu- 
ally small prostrate habit, very small leaves, most- 
ly glabrous little inflorescences, capsules often with 



78 



FIELDIANA: BOTANY 



thin hairs along the edges, and seeds with well- 
defined transverse ribs. 

Chamaesyce serpens (H.B.K.) Small, Fl. South- 
eastern U.S. 709, 1333. \9Q3.Euphorbiaserpens 
H.B.K., Nov. gen. sp. 2: 52. 1817. Figure 6. 

Herbs to 30 cm wide, prostrate, much branched, often 
rooting at the nodes, leafy stems 0.2-1.3 mm thick, gla- 
brous or minutely puberulent with thin hairs to 0.5 mm 
long; stipules 0.3-1 mm long, mostly triangular with 
lacerate margins, occasionally with 2 rounded glands at 
the base, often white. Leaves with petioles 0.5-1.5 mm 
long, 0.2-0.3 mm thick, glabrous; leaf blades 1.5-7 mm 
long, 0.7-4.5 mm wide, ovate-oblong to oblong or ovate- 
orbicular, apex bluntly obtuse or rounded and emargin- 
ate, margin entire or subserrate, base slightly asymmetric 
with 1 side distally rounded or subcordate and the other 
side less so, drying chartaceous, glabrous, venation pal- 
mate or subpalmate, usually obscure. Inflorescences ter- 
minal or becoming pseudoaxillary, usually of solitary (2) 
cyathia borne on peduncles 0.3-1.2 mm long, to 2.3 mm 
long in fruit, bracts glabrous; cyathia with involucres 
0.8-1 .3 mm long, 0.5-1 . 1 mm wide, obconic, with small 
deltoid lobes, petaloid appendages ca. 0.3 mm long, 0.4- 
0.5 mm wide, transversely oblong, white. Fruits 1.2-1.7 
mm long, 1.3-1.7 mm wide, ovoid with truncated base 
and somewhat flattened sides, glabrous, borne on a stipe 
0.4-1 .3 mm long, columella 0.8-1 .3 mm long; seeds 0.8- 
1 . 1 mm long, 0.4-0.6 mm wide, with 4 rounded corners 
in cross-section, sides somewhat concave, transverse ribs 
absent or poorly developed, pale brown. 

Plants of open sunny areas along margins of 
freshwater lakes, lagoons, and dried depressions; 
0-200 m elevation. Probably flowering and fruit- 
ing throughout the year (collected in Costa Rica 
in April and July). In Costa Rica, this species has 
only been collected near the mouth of the Rio 
Tempisque, Guanacaste Province. The species now 
ranges widely, from the midwestern United States 
and southernmost Canada to Peru and the West 
Indies. 

Chamaesyce serpens is recognized by its pros- 
trate habit, minute closely set leaves, generally gla- 
brous parts, and seeds lacking well-developed 
transverse ribs. 

Chamaesyce thymifolia (L.) Millsp., Publ. Field 
Columb. Mus., Bot. Ser. 2: 413. 1915. Euphor- 
bia thymifolia L., Sp. PI. 454. 1953. Figure 6. 

Herbs, usually prostrate and forming small mats to 
40(-60) cm wide, stems often reddish, internodes 1.5- 
12 mm long (less often to 20 mm), leafy stems 0.5-1.7 
mm thick, with thin whitish hairs 0. 1-0.5 mm long, often 
glabrous on the lower surface or with longitudinal lines 
of hairs; stipules 0.5-1.8 mm long, united at the base, 
triangular or with linear teeth. Leaves with petioles 0.4- 
1 mm long, 0.2-0.4 mm thick, puberulent or glabrous, 



drying reddish; leaf blades 3-8(-10) mm long, l-4(-5) 
mm wide, oblong to ovate-oblong or ovate-elliptic, apex 
bluntly obtuse to rounded, margin subserrate or with 3- 
7 teeth/side 0.1-0.2 mm high, base asymmetric with a 
straight cuneate side and a rounded truncate or subcor- 
date side, drying stiffly chartaceous, glabrous above, gla- 
brous or sparsely puberulent beneath, venation subpal- 
mate with a midvein and 2 (3) major laterals from the 
base, 2 veins 1-3/side of the midvein, usually obscure. 
Inflorescences usually axillary and inconspicuous, 2-6 
mm long, cyathia 1-3 and congested on short (1 mm) 
peduncles, bracts minute; cyathia with involucres 0.8-1 
mm long, 0.6-0.8 mm wide, obconic, glands 0. 1-0.2 mm 
wide, elliptic to suborbicular, petaloid appendages in 2 
unequal pairs or absent, reddish; anthers ca. 0.3 mm 
wide, with 2 rounded thecae; ovary ca. 0.7 mm long with 
styles 0.3 mm long. Fruits 1-1.3 mm long, 0.9-1.2 mm 
wide, ovoid-oblong or ovoid with truncated base, usually 
with minute appressed hairs, often with 3 somewhat 
flattened sides, closely subtended by the calyx-like cy- 
athium (without a developed stipe and splitting the cy- 
athium at maturity), columella 0.7-0.9 mm long, slen- 
der; seeds 0.6-0.9 mm long, 0.3-0.4 mm wide, 4-sided 
in cross-section, with 3-4 prominent transverse ribs on 
each side, pale brown. 

Common plants of open sunny sites in both ev- 
ergreen and seasonally deciduous areas, 0-600(- 
1 200) m elevation. Probably flowering and fruiting 
throughout the year (collected mostly in Decem- 
ber-August). This species is often encountered near 
the seashore and in open disturbed sites such as 
river edges and roadsides. The species ranges widely 
throughout the tropics and subtropics of the 
Americas and the Old World. 

Chamaesyce thymifolia is recognized by its usu- 
ally prostrate mat-forming habit, usually closely 
spaced little leaves, small axillary inflorescences 
with few cyathia, and puberulent fruits lacking 
stipes. It is often called golondrina in Central 
America. 



Cleidion Blume 

Trees or shrubs, monoecious or dioecious, glabrous 
or puberulent with simple hairs; stipules present, free, 
caducous. Leaves alternate, simple, margins usually den- 
tate, venation pinnate, often with 2-many glands or glan- 
dular hairs at the base of the blade, domatia of tufted 
hairs present or absent. Inflorescences axillary, usually 
I/node, unisexual, spicate (<3) or thyrsoid to racemiform 
(2), bracts eglandular, flowers small and pedicellate. Male 
flowers with united calyx splitting at anthesis into 34 
valvate lobes, petals and disk absent; stamens 30-80, 
densely crowded on a convex receptacle, filaments short 
and free, in several vertical series, anthers 4-thecous, 
connective usually expanded distally into an appendage 
or gland; pistillode absent. Female flowers with 3-6 im- 
bricate calyx lobes, petals absent, disk and staminodes 
absent; ovary 3- (2-)locular, ovules 1 /locule, styles united 



BURGER & HUFT: FLORA COSTARICENSIS 



79 



only at the base, each style deeply divided and bifid to 
2-parted (= 6 long style branches). Fruits capsules break- 
ing into 3 (2, 1) 2-valved cocci, columella slender; seeds 
subglobose and smooth, ecarunculate, endosperm pres- 
ent, cotyledons broad, thin. 

A pan tropical genus of about 25 species, with a 
majority of species in Australasia, several species 
in South America, and a single species in western 
Africa. One species ranges northward to Mexico, 
while Cleidion membranaceum Pax & K. Hoffm. 
(= C. woodsonianum Croizat) reaches central and 
eastern Panama. 

Cleidion castaneifolium Mull. Arg., Linnaea 34: 
184. 1865. Alchornea oblongifolia Standl., Car- 
negie Inst. Wash. Publ. 46 1 (Botany of the Maya 
Area 4): 66. 1935. C. oblongifolium (Standl.) 
Croizat, J. Arnold Arbor. 24: 166. 1943. Figure 
12. 

Shrubs or small trees 3-12 m tall, trunks 10-25 cm 
diam., dioecious, leafy stems 1.5-5 mm thick, at first 
minutely (0.1-0.2 mm) puberulent, soon glabrescent; 
stipules 2-4 mm long, 1 mm wide at base, narrowly 
triangular, acute, appressed-puberulent, caducous. Leaves 
with petioles 14-52 mm long, 0.8-1.8 mm thick, thick- 
ened (2-3 mm) at apex and base and often geniculate, 
glabrous or minutely (0. 1 mm) puberulent; leaf blades 
9-26 cm long, 4.5-12 cm wide, elliptic-oblong, elliptic, 
elliptic-ovate or oblong, apex acuminate with narrow tip 
7-25 mm long, margin subentire or with 15-18 prom- 
inent (0.5-2 mm) glandular teeth/side, base obtuse to 
acute, base often with lateral glands along the edge or 
with imbedded flat glands, drying thinly to stiffly char- 
taceous, glabrous above and below (rarely with domatia, 
Grayum et al. 8961), 2 veins 6-10/side, 3 veins some- 
times subparallel. Male inflorescences 2.5-13 cm long, 
rachis 0.6-0.9 mm thick, glabrous or puberulent, glom- 
erules with 2-12 flowers, pedicels 1-4 mm long, 0.1-0.2 
mm thick, glabrous; $ flowers glabrous externally, buds 
1.5-2 mm diam., globose, androecium 1.5-2 mm wide 
at base, hemispheric, filaments 0-0.4 mm long, anthers 
closely compressed, 0.3-0.4 mm wide, opening apically. 
Female inflorescences 1-4 cm long with 1-4 flowers, 
rachis 0.6-1 mm thick, minutely puberulent, bracts 0.4- 
1 mm long, subtending solitary pedicellate flowers; 9 
flowers with 3 calyx lobes 1-2 mm long, puberulent, 
ovary ca. 1.4 x 2 mm, oblate, style branches 3.5-9 mm 
long, 0.3-0.5 mm thick, puberulent on the inner face. 
Fruits 7-10 mm long, 14-18 mm wide, usually with 3 
rounded lobes and flattened distal surface, rounded be- 
low, woody walls ca. 0.6 mm thick, columella 6-8 mm 
long, widened distally; seeds 7-9 mm diam., subglobose, 
smooth and lustrous, dark, or grayish. 

Plants of evergreen lowland forest formations, 
20-700 m elevation (to 1 700 m in Mexico). Flow- 
ering primarily in January-October; fruiting in 
January-April. The species ranges from southern 
Mexico to Ecuador. 



Cleidion castaneifolium is distinguished by its 
larger pinnately veined leaves with denticulate 
margin and petioles thickened at the base and apex, 
spiciform 3 inflorescences with many anthers 
forming a dome-shaped androecium, few 9 flowers 
usually with six style branches, and flesh-covered 
fruits. The thickened base and apex of the petioles 
often dry dark. The distribution in Costa Rica is 
unusual: the Talamanca valley and the moist for- 
ests from Volcan Orosi to Upala on the Caribbean 
slope and in the evergreen Pacific lowlands (Res. 
Biol. Carara to Osa). These plants may resemble 
Sorocea and Trophis of the Moraceae. 



Cnidoscolus Pohl 

REFERENCE G. Breckon, Studies in Cnidosco- 
lus (Euphorbiaceae) 1 . Jatropha tubulosa, J. lieb- 
mannii and allied taxa from Central Mexico. Brit- 
toniaSl: 125-148. 1979. 

Herbs, shrubs, or small trees, monoecious, stems usu- 
ally armed with slender sharp stinging hairs, with whitish 
latex; stipules free, small. Leaves alternate, simple, pet- 
ioles usually long, with glands at the base of the blade, 
with stinging hairs, blades usually palmately lobed with 
shallow to deep sinuses, venation palmate (pinnate). In- 
florescences terminal or pseudoaxillary, solitary, usually 
bisexual with proximal 2 flowers and distal $ flowers, 
paniculate (of open dichasia with cymose branching), 
bracts and bracteoles small. Male flowers with whitish 
petaloid perianth of 1 whorl (calyx) united to form a 
distinct tube with 5 distal imbricate lobes, petals absent, 
disk annular, extrastaminal; stamens 8-10(-25), outer 
filaments free and inner usually connate (or all united); 
slender staminodes (= pistillode?) sometimes present at 
apex of staminal column. Female flowers with white pet- 
aloid perianth (calyx), calyx usually 4-5 parted to near 
the base, petals and staminodes absent, disk annular; 
ovary 3- (5-)locular, ovule 1/locule, styles 3 (5), free, 
bifid to laciniate. Fruits capsules with 3 (5) 2-valved 
1 -seeded cocci; seeds carunculate, with much endo- 
sperm, embryo straight, cotyledons broad. 

An American genus of ca. 50 species with cen- 
ters of diversity in Mexico and Brazil. The North 
American material was studied by G. Breckon and 
annotated in 1974. The genus is easily recognized 
because of its stinging hairs. Standley and Stey- 
ermark (1 949, p. 59) remark that these may be the 
most painful of all the stinging plants in Central 
America; compare Urera (Urticaceae), Wigandia 
(Hydrophyllaceae), and Loasa and Mentzelia (Lo- 
asaceae). The plants are also distinctive because 
of their large lobed leaves with deep sinuses, glands 
at the apex of long petioles, few-branched stems, 



80 



FIELDIANA: BOTANY 



long-pedunculate dichasia, <3 flowers with corolla- 
like calyx tube, 2 flowers with separate corolla-like 



perianth parts, and three-lobed capsules covered 
with stinging hairs. 



Key to the Species of Cnidoscolus 

1 a. Glands at the apex of the petiole minutely digitate, sometimes lacking or obscure in drying; herbs 
or succulent stemmed subshrubs 0.5-2.5 m tall, stems and leaves with many stinging hairs to 10 
mm long; leaves 3-5-lobed, the margins entire or with small (3 mm) dentate lobes; <3 perianth lobes 
ca. 2 mm long [seeds 10-12 mm long, ca. 3 m thick; deciduous and partly deciduous formations, 
0-300 m elevation] C. urens 

Ib. Glands at the apex of the petiole 1-2, flat or rounded; shrubs or small trees 1-7 m tall, stems and 
leaves with stinging hairs to 7 mm long; leaves with 3-5 large lobes and the margins with additional 
prominent acute to acuminate lobes; <3 perianth lobes ca. 4 mm long 2 

2a. Seeds 6-8 mm long, ca. 3.5 mm thick; deciduous or evergreen areas, often planted in hedges, 0- 
1 200 m elevation C. aconitifolius 

2b. Seeds ca. 12 mm long, 4.5 mm thick; rarely collected in southern Central America . . . C. tubulosus 



Cnidoscolus aconitifolius (Miller) I. M. Johnston, 
Contr. Gray Herb. 68: 86. 1923. Jatropha acon- 
itifolia Miller, Gard. Diet. ec. 8, 1768. Figure 2. 

Shrubs or small trees l-4(-7) m tall, leafy stems 5-12 
mm diam., glabrous or with slender stinging hairs 0.7- 
3 mm long, sometimes with broad-based thorn-like 
structures to 8 mm high; stipules ca. 3 x 2 mm, with 
digitate margin, caducous. Leaves with petioles 6-30 cm 
long, 1.5-9 mm thick, with few or many sharp-tipped 
stinging hairs 0.5-6 mm long, hairs simple or with basal 
stalk to 3 mm long, flat disk-like glands ca. 1.5 mm wide 
at or near the apex; leaf blades 1 1-28 cm long, 14-36 
cm wide, usually with 3 or 5 larger distal lobes and 2 
smaller basal lobes, apex acuminate or acute, tip 5-20 
mm long, margins with similar acute to acuminate lobes, 
base broadly to narrowly cordate, drying membrana- 
ceous, greenish or brown, with a few scattered sharp hairs 
above and below, venation palmate with 3 or 5 (7) prom- 
inent palmate veins. Inflorescences 1 1-40 cm long, to 
55 cm in fruit, 2-10 cm wide, broadly unbelliform di- 
chasia, peduncles 1-35 cm long, 2-5 mm thick, with 
stinging hairs 0.3-6 mm long, <5 flowers subsessile, 9 flow- 
ers short-pedicellate. Male flowers minutely papillate- 
puberulent, perianth white, calyx tube 3-6 mm long, 
tubular or funnelform, lobes 2.4-4 mm long, 2.2-3 mm 
wide, rounded; anthers 1-1.4 mm long. Female flowers 
minutely puberulent or glabrous, calyx lobes 6-1 1 mm 
long, 1.5-2.5 mm wide, oblong-obovate, white, decid- 
uous and leaving a truncated cup 0.7 mm long, ovary 
2-4 mm long, style branches 2-3 mm long, distally di- 
vided. Fruits 12-18 mm long, ca. 12 mm wide, oblong, 
covered with stinging hairs ca. 3 mm long, columella ca. 
7 mm long; seeds 6-8 mm long, 4-5.5 mm wide, 3-3.8 
mm thick, caruncle ca. 2 mm wide. 

Plants of evergreen or deciduous areas, 0-1200 
m elevation. Flowering in April-July. Probably 
native to southern Mexico but often found in 



hedgerows and gardens and apparently naturalized 
in the Guanacaste lowlands. This species now 
ranges from Mexico to Peru. 

Cnidoscolus aconitifolius is recognized by larger 
stature and fewer stinging hairs (compared to C. 
urens), larger deeply lobed leaves with prominent 
acuminate lobes along the margins, and flat dis- 
coid glands above the petiole attachment. The 
stinging hairs are often few or absent. The young 
shoots and leaves have been used as a cooked 
vegetable (Standley, 1937), and the trees are used 
as fence posts. Chicasquil is a common name. 

Cnidoscolus tubulosus (Mull. Arg.) I. M. Johnston, 
Contr. Gray Herb. 68: 86. 1923. Jatropha tub- 
ulosa Mull. Arg., Linnaea 34: 212. 1865. J. tub- 
ulosa var. quinqueloba Mull. Arg., J. cordifolia 
Pax, Pflanzenreich IV. 147: 107. 1910. C. cor- 
difolius (Pax) I. M. Johnston, Contr. Gray Herb. 
68: 86. 1923. 

Shrubs or small trees, 2-7 m tall, trunks to 30-40 cm 
diam., leafy stems 4-18 mm thick with sharp stinging 
hairs 1.5-7 mm long, articulated at the base, with or 
without minute (0.2 mm) thin hairs; stipules ca. 2 mm 
long and 2.5 mm wide at the base. Leaves with petioles 
8-35 cm long, 1.5-5 mm thick, with slender sharp sting- 
ing hairs and often with minute thin hairs, with 1-2 
rounded flat sessile glands near the adaxial apex; leaf 
blades 1 1-35 cm long, 14-38 cm wide, with 3 prominent 
distal lobes separated by wide or narrow sinuses 3-12 
cm deep, usually with 2 additional lateral/basal lobes, 
apex of the major lobes acuminate, margins with short 
(0.5-6 mm) teeth separated by 5-1 5 mm, base shallowly 
or deeply cordate, drying thin-chartaceous, greenish or 
brown, with scattered thin sharp- tipped hairs 1-3 mm 



BURGER & HUFT: FLORA COSTARICENSIS 



81 



long on both surfaces, venation palmate with 5 major 
veins, 2 veins 10-15/side of midvein. Inflorescences 
usually bisexual, 6-40(-70) cm long, a compound di- 
chasium with multiple dichotomies, peduncles 4.5-46 
cm long, 1.5-8 mm thick, with stinging hairs, $ flowers 
subsessile in axils of basal dichotomies, $ flowers on 
pedicels ca. 1 mm long. Male flowers white, 1 1-15 mm 
long, minutely and densely puberulent externally, calyx 
tube ca. 6 mm long, 2-3 mm diam., lobes 4-5 mm long, 
2-3 mm wide, rounded at apex; anthers 1.5-1.8 mm 
long. Female flowers white, 10-15 mm long, perianth 
tube 5-6 mm long, ca. 3 mm diam. near base, lobes 5- 
6 mm long, persisting; ovary ca. 5 mm long, styles united 
for 1.5 mm, style branches ca. 4 mm long, twice bifid. 
Fruits 16-18 mm long, with few to many stinging hairs, 
oblong; seeds 12-13 mm long, ca. 8 mm wide, 4.5-5 
mm thick, elliptic in cross-section, broad surfaces smooth, 
notched at the base, caruncle 1-1.5 mm wide. 

Plants of partly deciduous and montane forest 
formations, 900-1700 m elevation in northern 
Central America. Probably flowering primarily in 
the wet season, May-November. The species rang- 
es from Mexico to Nicaragua and in Peru. 

Cnidoscolus tubulosus is recognized by its deeply 
lobed and dentate leaves, prominent stinging hairs, 
tubular perianth in both $ and 9 flowers, and larger 
seeds. We have not seen material of this species 
from Costa Rica or Panama. See discussion re- 
garding this species in Breckon (1979; cited above). 

Cnidoscolus urens (L.) Arthur, Torreya 21: 11. 
1921. Jatropha urens L., Sp. PI. 1007. 1753. J. 
adenophila Pax & K. Hoffm., Pflanzenreich 63 
(IV, 147, VII): 400. 1919. C. adenophilus (Pax 
& K. Hoffm.) Pax & K. Hoffm., Naturl. Pflan- 
zenfam. ed. 2, 19c: 166. 1931. C. urens ssp. 
adenophilus (Pax & K. Hoffm.) Breckon, Ann. 
Missouri Bot. Card. 75: 1114. 1988. Figure 2. 

Herbs or shrubs 0.5-2.5 m tall, stems usually succu- 
lent, leafy stems 3-10 mm thick, with many sharp sting- 
ing hairs 6-9 mm long, ca. 0.2 mm thick near base; 
stipules ca. 2 x 2 mm, laciniate-dentate, caducous. Leaves 
with petioles, 7-18 cm long, 1.5-3.5 mm thick, with 
short (0.2-0.3 mm) thin hairs and longer stinging hairs, 
glands at apex few to many, digitiform, 0.3-1 mm high 
but often obscure when dried; leaf blades 5-1 9 cm long, 
6-19 cm wide, with 3 large often obovate distal lobes 
and 2 smaller proximal lobes, apex short-acuminate to 
acute, margins entire or with short (1-3 mm) broad teeth, 
base broadly cordate, drying membranaceous, with short 
(0.1-0.3 mm) thin hairs on both surfaces, venation pal- 
mate with 5 major veins. Inflorescences 4-16(-22) cm 
long, 3-8(-l 2) cm wide, umbelliform dichasia, peduncles 
3-12 cm long, 1.6-3.5 mm thick, with short (0.2-0.4 
mm) thin hairs and stinging hairs to 4 mm long. Male 
flowers to 1 1 mm long, white, minutely puberulent or 
sometimes with stinging hairs, calyx tube funnelform or 
tubular, 4-7 mm long, 2-3 mm diam., lobes 2-4 mm 
long, ca. 1 .8 mm wide; anthers ca. 1 . 1 mm long. Female 



flowers white, minutely puberulent or glabrous, 5-6 mm 
long, corolla lobes ca. 5 x 1.5 mm, deciduous; ovary ca. 
2.5 mm long. Fruits 10-13 mm long, 9-11 mm wide, 
green with white stripes, with stinging hairs, walls ca. 0.6 
mm thick, columella ca. 8 mm long; seeds 8.5-10.5 mm 
long, 3.8-5 mm wide, 2.5-3.2 mm thick, whitish to gray, 
black or mottled, caruncle 2.5-3.2 mm wide, base slight- 
ly bilobed. 

Plants of deciduous or partly deciduous forests, 
0-300 m elevation (to 600 m in Guatemala). Flow- 
ering in June-January. The species ranges from 
eastern Mexico to Argentina. 

Cnidoscolus urens is distinguished by its dense 
covering of sharp stinging hairs, smaller stature, 
lobed leaves with usually unlobed margins, and 
seasonally dry open habitats. The glands above 
the apex of the petiole are often minutely digitate. 
The hairs sting severely, the pain sometimes per- 
sisting for many hours (Standley, 1937). This spe- 
cies is apparently represented by two distinctive 
subspecies in Panama (Breckon in Webster & Huft, 
1988; Webster & Burch, 1968). These plants have 
been called hierba santa in Costa Rica and chor- 
rera, chame, ortiga, and pringamoza in Panama. 



Codiaeum Adr. Jussieu 

Shrubs or small trees, usually monoecious, glabrous 
or with simple hairs; stipules present or absent. Leaves 
alternate, simple, petiolate, entire or lobed, usually co- 
riaceous, pinnately veined. Inflorescences axillary to dis- 
tal leaves, solitary or 2/node, racemose or spike-like with 
a long unbranched rachis, unisexual or bisexual with 1- 
2 proximal 2 flowers, flowers small, $ bracts with 1 flower, 
8 flowers 1-6/bract. Male flowers with 5 (3-6) calyx lobes 
or parts, imbricate in bud, petals small or rudimentary, 
disk of 5-15 free glands; stamens 15-100, borne on the 
elevated receptacle, filaments free, anthers erect; pistil- 
lode absent. Female flowers with calyx usually 5-parted, 
petals absent, disk cupulate, entire or lobed, staminodes 
absent; ovary 3-locular, ovules 1/locule, styles 3, simple 
and slender. Fruits capsules, globose or 3-lobed, breaking 
into 3 2-valved cocci, columella persisting; seeds carun- 
culate, endosperm carnose, cotyledons flat. 

A genus of ca. 15 species of Australasia and the 
western Pacific islands. One colorful ornamental 
species is now widely cultivated throughout the 
tropics and subtropics. 

Codiaeum variegatum (L.) Adr. Juss., Euphorb. 
Gen. Tent. 1 1 1, t. 9, f. 30. 1824. C. variegatum 
(L.) Blume, Bijdr. fl. Ned. Ind. 606. 1825. Cro- 
ton variegatus L., Sp. PI. ed. 3. 1424. 1764. Fig- 
ure 32. 



82 



FIELDIANA: BOTANY 



Shrubs and small few-branched treelets 1-5 m tall, 
leafy stems 3-10 mm thick, glabrous or glabrescent; stip- 
ules absent. Leaves with petioles 1-4 cm long, glands 
absent; leaf blades 5-35 cm long, 1-13 cm wide, shape 
extraordinarily variable in different cultivars (also vari- 
able on the same plant), usually long and narrow, nar- 
rowly obovate to oblanceolate, apex acute to rounded, 
margin entire, with or without 1-3 rounded lobes and 
sinuses (with a bladeless petiole-like portion in the center 
of the blade in some varieties), drying stiffly chartaceous 
to subcoriaceous, glabrous, lustrous, variously colored. 
Inflorescences 12-40 cm long, usually erect, unisexual, 
glabrous, spike-like with 1-3 3 flowers in sessile fascicles 
and pedicels 2-4 mm long. 

Codiaeum variegatum is native to the south- 
western Pacific and is now a favorite ornamental 
cultivar because of its brilliantly colored leaves 
mottled with dark green, yellow-green, yellow, rose- 
red, red, or purple. The blades often have paler 
colored areas around the major veins. The blades 
vary greatly in shape but are generally long and 
narrow and have entire margins. The plants are 
often used as hedges but are restricted to lower (0- 
900 m) elevations. Laurel, cintillo, and "garden 
croton" are common names. 



Conceveiba Aublet 

Small to large trees, dioecious, minutely stellate-pu- 
berulent, glabrescent; stipules paired at the leaf base, 
deciduous. Leaves alternate, simple, petioles often ge- 
niculate at the apex and thickened at the base (stipels 
absent); leaf blades slightly crenate-denticulate with gland- 
tipped lobes or sinuses, minutely stellate puberulent be- 
neath, venation palmate (in our species) or pinnate. Male 
inflorescences terminal or axillary, solitary, simple and 
racemose or branched and paniculate, often broad, flow- 
ers solitary or in sessile groups along the rachis, bracts 
small (glands not apparent), pedicels short; $ flowers with 
ovoid or spherical buds, calyx opening irregularly or 3- 
4 parted, corolla and disk absent; stamens ca. 1 6-many, 
filaments free, anthers dehiscing longitudinally, thecae 
rounded; pistillode absent. Female inflorescences ter- 
minal, solitary, narrowly spiciform racemes with a thick 
rachis and distant solitary flowers subtended by small 
broad-based bracts, lateral glands usually present at the 
base of the bracts, pedicels short and thick, borne directly 
on the rachis (C. latifolia) or on a very short articulated 
lateral branch of the rachis (C. pleiostemona); $ flowers 
with 5-8 narrow stiff imbricated puberulent sepals (al- 
ternating with large glands in C. latifolia), petals and 
disk absent, staminodes absent; ovary 3-4 locular, ovules 
1/locule, styles united only at base, thick, papillose adax- 
ially, bifid distally. Fruits fleshy and large, 3-costate, 
separating into 3 2-valved capsules; seeds large, carun- 
culate. 

A Neotropical genus of seven to nine species; 
all are South American, except the Costa Rican 



endemic, a recently discovered African species and 
an undescribed Panamanian species. The stellate 
nature of the pubescence is difficult to see because 
of the small size of the hairs. Herbarium material 
of our species was previously filed under Vecon- 
cibea; compare Alchornea. 

Conceveiba pleiostemona J. D. Smith, Hot. Gaz. 
54: 243. 1912. Veconcibea pleiostemona (J. D. 
Smith) Pax & K. Hoffm. Figure 20. 

Trees, 10-30 m tall, 25-100 cm dbh, large trunks 
sometimes fluted, leafy twigs 2-8 mm thick, with short 
(0.1-0.3 mm) appressed-stellate hairs and with longer 
(0.4 mm) straight or V-shaped hairs attached at the mid- 
dle; stipules 4-8 mm long, 0.7-1.2 mm wide, linear, 
appearing densely sericeous with ascending hairs, decid- 
uous. Leaves with petioles 2.2-12 cm long, 1-3 mm 
thick, minutely stellate-pubescent, sometimes drying 
darker and thinner along the terminal 4-5 mm; leaf blades 
5-22 cm long, 4-19 cm wide, broadly ovate to ovate- 
suborbicular, apex obtuse to rounded or with a short- 
acuminate tip 3-10 mm long, margin bluntly serrulate 
with 15-23 teeth/side, teeth 0.3-1 mm high and gland- 
tipped, base rounded to subcordate, drying stiffly char- 
taceous or subcoriaceous, glabrous or pubescent on the 
midvein above, minutely stellate-pubescent beneath, ve- 
nation palmate, 2 veins 4-6/side, 3 and 4 veins sub- 
parallel and perpendicular to the higher rank veins. Male 
inflorescences axillary or terminal, 7-20 cm long, simple 
and spicate or compound and paniculate with lateral 
branches to 4 cm long, peduncles 2-35 mm long, 0.7-2 
mm thick, minutely stellate-puberulent, bracts ca. 1 mm 
long, pedicels 0.5-1 mm long, drying black; $ flowers 
with spherical buds ca. 2 mm diam., perianth parts 1- 
2 mm long, mostly glabrous and drying black; stamens 
30-60, filaments 0.5-1.9 mm long (not 7-1 1 mm as in 
the original description), anthers 0.4-0.5 mm long. Fe- 
male inflorescences terminal, to 22 cm long in fruit, spi- 
ciform at first, rachis 2-3 mm thick, minutely stellate- 
puberulent, bracts 3-5 mm long, 1-2 mm wide at base, 
subtending a short lateral peduncle (becoming up to 10 
mm long in fruit), articulated below the short (1-3 mm) 
thick ( 1 mm) pedicels; 2 flowers with 5 sepals 3-5 mm 
long, 1 mm wide at base; ovary ca. 4.5 mm long, 3-angular 
in cross-section, style branches becoming 4-5 mm long 
and recurved, 0.5-0.7 mm thick. Fruits ca. 1.8 x 1.2 
cm, oblong with elevated longitudinal ridges and per- 
sisting style branches, green and fleshy, pedicels red; seeds 
ca. 10 x 8 mm, smooth, brown. 

Trees of Caribbean rain forest formations on 
well-drained soils, 50-600 m elevation. Flowering 
in June-July; fruiting in August-October. The spe- 
cies is known only from Costa Rica, ranging from 
just north of Tortuguero National Park to Amubri 
in the Talamanca valley. It probably occurs also 
in adjacent Nicaragua and Panama. 

Conceveiba pleiostemona is recognized by its 
large stature, minute stellate pubescence, broadly 
ovate palmately veined leaves with subparallel mi- 



BURGER & HUFT: FLORA COSTARICENSIS 



83 



nor venation, short-pedicellate <5 flowers with many 
stamens, and fleshy fruit on long narrow inflores- 
cences. The large size of these trees and their re- 
stricted flowering and fruiting season probably ac- 
count for the paucity of collections. The fruits are 
eaten by macaws (Aras ambigua). Compare the 
superficially similar Aparisthmium cordatum, 
which lacks the stellate hairs and has smaller cap- 
sular fruits. 



Croton Linnaeus 

REFERENCE G. L. Webster, A provisional syn- 
opsis of the sections of the genus Croton (Eu- 
phorbiaceae). Taxon 42: 793-823. 1993. 

Trees, shrubs or herbs, bisexual (monoecious) or uni- 
sexual (dioecious), sap often white or colored, stems with 
simple, stellate, scurfy or flat rounded peltate hairs; stip- 
ules small or absent, usually caducous. Leaves alternate 
or sometimes opposite at congested distal or flowering 
nodes, simple, petiolate, often with glands near the apex 
of the petiole or at the base of the blade, blades entire 
to deeply lobed, margins entire to serrate, venation pal- 
mate or pinnate. Inflorescences terminal or axillary, spi- 
cate to racemose (actually a condensed thyrse with a 
single unbranched rachis, but apparently branched or 
pseudopaniculate when distal leaves fail to develop), bi- 
sexual or unisexual, with 1-10 usually solitary 9 flowers 
at proximal nodes and many <5 flowers distally when 
bisexual, rachis usually pubescent, bracts and bracteoles 
small, 6 flowers often in sessile fascicles (cymules). Male 
flowers with 46 valvate or imbricate calyx lobes, petals 
usually 5 (4, 6, 0), receptacle usually pilose; stamens 8- 
50, filaments inflexed in bud and free, pistillode absent. 
Female flowers with 5-7 (4-10) calyx lobes, imbricate 
or valvate, petals or 5 and small, staminodes absent, 



disc entire or lobed; ovary with 3 (1, 2) locules, ovules 
1/locule, styles 3 (2), bifid or several times bifid. Fruits 
usually capsules with 3 (2) 2-valved cocci, columella 
usually persisting; seeds oblong in outline, rounded abax- 
ially, carunculate, endosperm present, embryo with broad 
flat cotyledons. 

A very large genus of ca. 800 species of tropical 
and warm-temperate regions. South America, the 
West Indies, and Mexico are important centers of 
species diversity. The stellate or lepidote hairs, 
narrow unbranched inflorescences, stamens in- 
flexed in bud, divided style branches, capsular 
fruits, and inapeturate pollen grains help distin- 
guish the genus. The glands near the apex of the 
petioles of some species can be quite striking, from 
sessile and saucer-like to stipitate and patelliform. 
Plants of this genus are sometimes conspicuous 
because their leaves turn bright yellow or orange 
before they are shed. 

The Costa Rican species of Croton include both 
wide-ranging species and local endemics with re- 
markably narrow ranges. Many species are poorly 
represented in herbaria, probably because they are 
part of open weedy or early secondary vegetation. 
A few can become tall trees, and these are not well 
collected. Many species display considerable vari- 
ation in leaf size, leaf form, pubescence, inflores- 
cences, and floral morphology. Such variation can 
make the determination of individual specimens 
very difficult. The genus is rich in alkaloids, and 
a number of species in Asia and South America 
have been used medicinally and for teas (cf. C. 
niveus). Some authors recognize the species of sec- 
tion Julocroton (Mart.) Webster as a genus. 



Key to the Species of Croton 

la. Young stems or petioles with appressed flat rounded centrally attached (peltate) hairs 0. 1-0.5 mm 
diam., sometimes with united radiating rays separated distally and resembling stellate hairs, stellate 

hairs present in a few species; stamens 10-1 5/flower 2 

Ib. Young stems lacking flat rounded centrally attached hairs, hairs sometimes centrally flattened with 
radiating hairs but these not united along their lateral edges to form a broad flat surface, the hairs 

stellate to scurfy and rounded, or simple; stamens 8-50/flower 10 

2a. Small (< 1 m) shrubs of the Caribbean seashore; leaves not > 4.5 cm long, upper (adaxial) 
surfaces of leaves with stellate hairs, young stems and lower (abaxial) surface of leaves with 

peltate-stellate hairs; $ flowers apetalous [stipules absent] C. punctatus 

2b. Shrubs or trees, not confined to the Caribbean seashore; mature leaves usually > 5 cm long, 
upper leaf surfaces glabrous or with flat rounded peltate hairs (stellate hairs also present in 
C. pachypodus and C. tonduzii), young stems and lower leaf surfaces with peltate hairs; <5 

flowers with petals (but sometimes small) 3 

3a. Venation palmate (basal 2 veins reaching the midpoint of the leaf margin or more distally) 

4 



84 



FIELDIANA: BOTANY 



3b. Venation pinnate or subpalmate 5 

4a. Leaf blades with entire or subentire margin, often silvery beneath with a dense covering 
of peltate hairs, 4-14 cm long, broadly ovate-orbicular to triangular; plants often grown 

in hedgerows, 0-1800 m elevation; seeds 6-16 mm long C. niveus 

4b. Leaf blades with prominently dentate margin, blades not silvery beneath, 9-18 cm 
long, ovate to ovate-elliptic or ovate-oblong; plants rare on the evergreen Pacific slope, 

400-900 m; seeds 5-6 mm long C. tonduzii 

5a. Seeds 20-28 mm long in capsules 3-5 cm long [trees to 30 m tall; leaves to 1 3 cm long, with 
2 lateral glands at the apex of the petiole; inflorescences mostly terminal, to 9 cm long; 300- 

1000 m] C. pachypodus 

5b. Seeds < 10 mm long, capsules to 1.5 cm long 6 

6a. Styles much divided with > 20 distal stigmatic branches/flower; leaf blades rounded and 

truncate to cordate at the base [8-26 cm long, ovate-oblong; evergreen forests] 7 

6b. Styles 2-3 times bifid, rarely with > 1 8 distal stigmatic branches/flower; leaf blades rarely 

rounded at the base, never cordate 8 

7a. Petioles without lateral glands at the apex, leaf blade rounded and truncated at the 

base, secondary veins 9-13 pairs; 6 flowers solitary on the rachis . . C. tenuicaudatus 

7b. Petioles with 2 lateral sessile glands at the apex, leaf blade rounded and cordate at base, 

secondary veins 11-17 pairs; $ flowers in groups of 5-1 1 C. skutchii 

8a. Apex of petiole lacking paired lateral or adaxial glands; wide-ranging and variable trees or 
shrubs [on both Pacific and Caribbean slopes, usually found at 0-700 m elevation; 2 veins 
8-13/side; styles bifid at base and with ca. 18 distal style branches; seeds 7-8 mm long] . . 

C. schiedeanus 

8b. Apex of petiole usually with 2 distinct stalked adaxial/lateral glands; restricted species . . 9 

9a. Leaves with few to many stellate-scurfy hairs on the upper surface, 2 veins 3-6/side; styles 

bifid in the distal half (6 distal branches/flower); seeds 6-7 mm long; known only from the 

Cordillera de Tilaran near Monteverde, 1400-1600 m elevation C. mexicanus 

9b. Leaves glabrous above, 2 veins 10-22/side; styles 2 times bifid (12 branches); seeds ca. 3.5 

mm long; rarely collected trees of the Caribbean slope at 200-800 m .... C. lanjouwensis 

lOa. (from Ib) Leaf blades often ovate (ovate-oblong) with the larger leaves usually becoming > 15 cm 

long, the base usually rounded and truncate to cordate, sessile or stipitate glands usually present 

near the apex of the petiole; pubescence usually of scurfy-stellate hairs; trees and shrubs not found 

in dry seasonally deciduous areas 11 

1 Ob. Leaf blades not ovate if becoming > 1 3 cm long, the base rounded and truncate to cordate only 
in leaves < 1 3 cm long, glands present or absent near the apex of the petiole, pubescence with 
various types of stellate or scurfy hairs; trees, shrubs, or herbs of both dry deciduous and wet 

evergreen formations 20 

1 la. Larger leaves often with 3 distal lobes and broad shallow sinuses (note that smaller leaves 
are usually unlobed), venation palmate; 9 calyx lobes 5-16 mm long [rarely collected species] 

12 

lib. Leaves with a single acute or acuminate apex (rarely with distal lobes), venation palmate to 

pinnate; 9 calyx lobes usually < 5 mm long (except in C. jimenezii) 13 

12a. Stamens ca. 1 1 /flower; 9 calyx lobes 5-7 mm long, styles much-branched; seeds ca. 5 
mm long; leaves, stems, and inflorescences not yellowish white with dense tomentulous 

pubescence C. smithianus 

12b. Stamens ca. 50/flower; 2 calyx lobes 8-16 mm long, styles 2 times bifid; seeds ca. 7 
mm long; leaves, stems and inflorescences with a dense tomentum of yellowish white 

hairs C. speciosus 

\ 3a. Venation pinnate in larger and smaller leaves, length of leaf blade often twice the width, 

often ovate-oblong and truncated at base 14 

1 3b. Venation palmate or subpalmate in larger leaves, length of leaf blade usually less than twice 

the width, usually ovate and subcordate at the base 17 

1 4a. Plants growing at 0-700 m elevation in Costa Rica; glands at the apex of the petiole 

BURGER & HUFT: FLORA COSTARICENSIS 85 



usually 2, sessile; stamens ca. 14, anthers 1-1.5 mm long; leaf blades often oblong . . 

C. billbergianus 

14b. Plants at (0) 800-2300 m in Costa Rica; glands at the apex of the petiole 2-7, often 

stalked; stamens 14-33, anthers 0.6-0.9 mm long; leaf blades often ovate 15 

1 5a. Leaf blades rarely > 1 5 cm long; stellate hairs compact (ca. 0.2 mm diam.) and usually 
flat, petiole with 2 lateral stalked glands at apex; stamens 14-16; seeds 6-7 mm long 

[Cordillera de Tilaran at 1400-1600 m elevation] C. mexicanus 

1 5b. Larger leaf blades usually > 1 5 cm long; stellate hairs often elevated and prominent; 
petiole with 2-9 glands at adaxial base of blade; stamens 14-33; seeds 4-5 mm long 

16 

16a. Calyx lobes of 9 flowers 2.5-9 mm long, oblong; pubescence with many small brownish 
scurfy hairs and some stellate hairs [<5 flowers sometimes present with proximal 9 flowers 
on bisexual inflorescences; seed ca. 4 x 3 mm; 1000-2500 m, Volcan Barva to San 

Isidro] C. jimenezii 

1 6b. Calyx lobes of 9 flowers 1 .5-4 mm long, usually triangular; pubescence mostly of whitish 

or yellowish hairs, scurfy to stellate 17 

1 7a. Seeds 6-8 mm long, surfaces smooth; glands 2 and sessile near the apex of the petiole; stamens 
ca. 15; 9 and <5 calyx united ca. 50% and conspicuous; plants restricted to the eastern Meseta 

Central and around Cartago, 900-1600 m elevation C. hoffmannii 

17b. Seeds 3.5-6 mm long, usually rugulose; glands 2-12 at the apex of the petiole and sessile or 

stipitate; stamens 15-33; and without the preceding combination of characters 18 

18a. Plants restricted to the Chiriqui Highlands at 1300-2100 m; leaf blades usually less than 14 
cm long and cordate [seeds 5-6 mm long; <5 flowers present with the proximal 9 flowers on 

bisexual inflorescences, stamens 25 40/flower] C. pungens 

18b. Plants widely distributed and common, 0-2100 m elevation; larger leaf blades more than 15 
cm long, cordate or truncate (the following two species are very similar and can be difficult 

to separate when bisexual inflorescences are lacking) 19 

19a. Male flowers present with proximal 9 flowers on bisexual inflorescences, flowers usually in 
glomerules (cymules) along the rachis; 9 flowers pedicellate, & flowers mostly in fascicles along 

rachis. stamens 1 3-22/flower; seeds 2.8-5 mm long C. draco 

19b. Male flowers not present with proximal 9 flowers on bisexual inflorescences, flowers often 
solitary along the rachis; 9 flowers subsessile; <3 flowers usually 1 -few/bract along the rachis, 

stamens 18-3 I/flower; seeds 4.8-5.7 mm long C. xalapensis 

20a. (from lOb) Leaves with 3 prominent distal lobes separated by deep narrow sinuses, 2 additional 
smaller basal lobes often also present [seeds ca. 5 x 3 mm, oblong; herbs to 1.5 m tall in open 

sunny sites in seasonally dry lowlands] C. lobatus 

20b. Leaves lacking 3 prominent distal lobes and deep sinuses 21 

2 la. Plants of seasonally very dry deciduous areas in the Guanacaste lowlands (0-500 m) 22 

21b. Plants of evergreen or partly deciduous forest formations, above 500 m elevation in Guanacaste 

and in other areas 27 

22a. Leaf blades silvery white or bright grayish white beneath; stipules often rounded and leaf- 
like in texture; 9 sepals broadly ovate and often laterally reflexed [stamens 15; glands absent 

or minute at apex of petiole] C. yucatanensis 

22b. Leaf blades not silvery white or bright grayish white beneath, often pale grayish; stipules not 

rounded or leaf-like; 9 sepals not broadly ovate 23 

23a. Leaf blades not exceeding 3.5 cm in length [glands absent at the apex of the petiole; plants 
not exceeding 1 m in height and rarely collected; stamens ca. 11; seeds 4.5-4.8 mm long] 

C. ovalifolius 

23b. Leaf blades often exceeding 3.5 cm in length 24 

24a. Venation pinnate or subpalmate, shrubby plants 25 

24b. Venation palmate, herbs or shrubs 27 

25a. Glands 24 at the apex of the petiole, blades lanceolate to narrowly elliptic or ovate, 
with prominent denticulate margin, venation pinnate; commonly collected in many 
sites [stamens 1 1 ; seeds 3.54 mm long] C. jutiapensis 



86 FIELDIANA: BOTANY 



25b. Glands absent at the apex of the petiole, blades ovate to ovate-elliptic, ovate-oblong 

or ovate-triangular, with subentire margin; uncommon in Costa Rica 26 

26a. Venation subpalmate, 2 veins 3-6 pairs, blade not cordate at base, thinly chartaceous; 

stamens 1 5; seeds 5-5.5 mm long C. sphaerocarpus 

26b. Venation pinnate, 2 veins 5- 1 pairs, blade often subcordate at base, stiffly chartaceous; 

stamens ca. 1 1 ; seeds not seen C. axillaris 

27a. (from 21b and 24b) Plants weak-stemmed weedy annuals, rarely > 1 m tall; wide-ranging species 

[stellate hairs with thin rays, not scurfy; stamens 8-12; seeds 3-4 mm long] 28 

27a. Plants woody shrubs and trees, 0.3-25 m tall; wide-ranging or locally endemic species 31 

28a. Stalked or sessile glands absent at the apex of the petiole, leaf blades drying pale greenish 
above and whitish below with a dense to men turn of stellate hairs, blades 2-15 cm long . . 

C. argenteus 

28b. Stalked or sessile glands usually present at the apex of the petiole, leaf blades drying green 
or dark green above, not whitish and densely tomentulose beneath, blades 1-9 cm long . . 

29 

29a. Leaf blades elliptic-lanceolate to narrowly triangular, conspicuously dentate with teeth 2-5 
mm high [hairs on stems to ca. 1 mm long; anthers 0.3-0.4 mm long; evergreen areas 0-800 

m elevation] C. trinitatus 

29b. Leaf blades ovate to narrowly oblong, with margins crenate or rounded-dentate with teeth 

1-3 mm long 30 

30a. Glands at apex of petiole stipitate; hairs on stems appearing simple and 1-3 mm long, usually 
retrorse; leaf blades broadly ovate to ovate-elliptic; floral bracts with slender gland-tipped 
segments [anthers 0.4-0.5 mm long]; deciduous and evergreen areas, 0-1700 m elevation 

C. hirtus 

30b. Glands at apex of petiole sessile or subsessile; hairs on stems stellate with rays to 1 mm long; 
leaf blades narrowly oblong to broadly ovate; floral bracts without glands or gland-tipped 

hairs; rarely collected in Central America C. glandulosus 

3 la. Small (< 1 m) shrubs found only near the Caribbean seashore; stems and lower (abaxial) surface 

of leaves with peltate-stellate hairs [leaves to 4.5 cm long] C. punctatus 

3 1 b. Shrubs or trees, usually > 1 m tall and not confined to the Caribbean seashore; peltate hairs absent 

or with flat peltate-like hairs in C. mexicanus 32 

32a. Largest leaves 6-10 cm long, usually densely pubescent; small shrubs of open sites at 1 100-1600 

m elevation around the Meseta Central 33 

32b. Largest leaves 8-22 cm long, sparsely to densely pubescent; taller shrubs or trees not collected 

around the Meseta Central 34 

33a. Calyx lobes of 9 flowers with slender naked gland-tipped hairs 1-2 mm long; petioles lacking 

stalked glands at the apex, 2 veins 4-13/side; stamens 15 C. decalobus 

33b. Calyx lobes of 2 flowers without slender gland-tipped hairs; petioles with 2 stalked glands at 

the apex, 2 veins 3-7/side; stamens 9-1 1 C. ortholobus 

34a. Leaf blades membranaceous to thinly chartaceous, up to 22 cm long, usually elliptic to ovate- 
lanceolate, hairs of lower leaf surface with fewer than 1 2 slender rays; shrubs or small trees of 

evergreen forests 50-800 m elevation 35 

34b. Leaf blades stiffly chartaceous, to 16 cm long, usually ovate to ovate-elliptic, hairs of lower leaf 
surfaces with 1 3 or more slender rays; trees of lowland rain forests or cloud forests and partly 

deciduous forests 36 

35a. Leaves alternate or opposite at some nodes, blade margins usually with prominent (3-5 mm) 
teeth, stalked yellowish glands often present in the sinuses of the margin, small (0.3 mm) 
yellowish glands not usually present on the lower surfaces, blades drying brown or dark green 

C. brevipes 

35b. Leaves alternate, margins with few small teeth or subentire, margin lacking stalked glands, 
small yellowish glands present near vein axils on the lower leaf surface, blades drying blackish 

C. sp. A 

36a. Leaves without lateral glands at apex of petiole; blades bright whitish tomentose beneath; stellate 



BURGER & HUFT: FLORA COSTARICENSIS 87 



hairs not peltate or scurfy; deciduous and partly deciduous forests [700-1 100 m elevation; stamens 
ca. 1 2; seeds 4-5 mm long] C. sp. aff. yucatanensis 

36b. Leaves usually with 2 lateral or adaxial glands at apex of petiole; blades not densely whitish 
tomentose beneath; stellate hairs often peltate or stellate-scurfy; evergreen forests 37 

37a. Leaf blades mostly ovate-elliptic with fewer than 6 pairs of 2 veins, pubescence of stems and 
inflorescences mostly flat-stellate; inflorescences simple; seeds 6-7 mm long; 1300-1500 m ele- 
vation C. mexicanus 

37b. Leaf blades mostly ovate-lanceolate with more than 8 pairs of 2 veins; pubescence of stems and 
inflorescences with thick stellate-scurfy hairs; inflorescences often with 2-4 long branches; seeds 
4-5 mm long; 200-800 m elevation C. billbergianus 



Croton argenteus L., Sp. PI. 1004. 1753. Julocro- 
ton argenteus (L.) Didr., Vidensk. Meddel. 
Dansk. Naturhist. Foren. Kobenhavn 1857: 134. 
1857. Figure 16. 

Annual herbs 0.2-1 m tall, bisexual, leafy stems 0.8- 
7.5 mm thick, stellate-pubescent with appressed hairs 
0.3-0.5 mm diam. or with long rays to 0.9 mm; stipules 
4-1 1 mm long, linear-subulate, simple or divided dis- 
tally, with hairs to 1.4 mm long. Leaves often closely 
congested beneath the inflorescences (becoming pseu- 
doverticellate), petioles 3-105 mm long, 0.7-2 mm thick, 
appressed stellate-pubescent, glands absent at apex; leaf 
blades 1.8-10(-15) cm long, 1.2-6(-8) cm wide, ovate 
to ovate-oblong, apex bluntly obtuse to rounded, margin 
minutely or obscurely denticulate, base obtuse or cuneate 
to subtruncate, drying chartaceous and pale grayish green 
beneath, stellate-pubescent with appressed hairs 0. 1-0.4 
mm diam., venation palmate with usually 5 major veins 
from the base, 2 veins 3-4/side of the midvein. Inflo- 
rescences terminal, bisexual, 1-4 cm long, often sub- 
tended by small (15 x 12 mm) leaves, congested and 
resembling a capitulum, bracteoles ca. 3 mm long, sub- 
tending solitary flowers, $ flowers proximal, pedicels to 
5 mm long in fruit, 6 flowers with pedicels ca. 2 mm 
long. Male flowers with calyx 1.5-2 mm long, sepal lobes 
ca. 1 mm long, petals 2-3 mm long, 0.3-0.4 mm wide, 
glabrous except on the margin; stamens ca. 11, filaments 
minutely hirsutulous, anthers 0.6-0.8 mm long. Female 
flowers with 5 unequal sepals, 6-8 mm long in fruit, 
petals absent, disk with 5 unequal lobes, ovary stellate- 
tomentellous, styles distally 4 times bifid. Fruits ca. 5 
mm long, borne on pedicels 3-5 mm long, sepals 6-8 
mm long and 3.5-6 mm wide, columella 3-4.5 mm long; 
seeds 3.2-3.8 mm long, 2.4-3 mm wide, ca. 2.2 mm 
thick, rounded-oblong, caruncle ca. 1.8 mm wide. 

Weedy plants of open sunny sites in seasonally 
dry habitats, 0-300 elevation. Collected with flow- 
ers in January-February, May, and August in Cos- 
ta Rica and Nicaragua. While rarely collected in 
Central America, it may be locally common. The 
species ranges disjunctly from Texas to Argentina. 

Croton argenteus is recognized by its herbaceous 
habit, the soft grayish green color of the leaves 
(especially the often whitish undersides), palmate 
venation with usually five major veins, appressed 
stellate hairs, short inflorescences often enclosed 



within subtending leaves, and restriction to sea- 
sonally deciduous vegetation. The paucity of col- 
lections from southern Central America suggests 
that the species is a recent introduction. Superfi- 
cially, these plants resemble a number of weedy 
Malvaceae. 

Croton axillaris Mull. Arg., Linnaea 34: 126. 1865. 

Shrubs or small trees 1-3.5 m tall, apparently unisex- 
ual, leafy stems 2-4 mm thick, densely pubescent with 
pale yellowish stellate hairs but soon becoming dark and 
glabrescent; stipules 4-6 mm long, ca. 1 mm wide at 
base, linear, densely stellate-pubescent. Leaves with pet- 
ioles 1 2-23 mm long, 1 .2-1 .8 mm thick, densely stellate- 
pubescent, hairs to 1.5 mm long, glands absent at apex; 
leaf blades 6-14 cm long, 3-8 cm wide, ovate-triangular 
to ovate-oblong or oblong, apex acute to acuminate with 
a narrow tip, margin subentire, base rounded and trun- 
cate to subcordate, drying thick-chartaceous, upper sur- 
face with minute (0.2-0.4 mm) stellate hairs on a slightly 
raised base, hairs with 5-7 lateral rays and 1 longer cen- 
tral ray, lower surface densely covered with short-stalked 
stellate hairs to 1 mm wide, venation pinnate, 2 veins 
8-1 8/side. Male inflorescences terminal on short axillary 
shoots before the leaves expand, 4-7 cm long, rachis ca. 
1 mm thick, whitish stellate-pubescent, bracts 1-3 mm 
long, caducous, pedicels 1-3 mm long; 6 flowers ca. 4 
mm wide, densely stellate-tomentose on the exterior, 
calyx lobes ca. 2 mm long, petals ca. 0.8 mm wide, 
oblanceolate, glabrous abaxially and densely puberulent 
on the inner face; stamens 1 1 , filaments 34 mm long, 
sparsely puberulent, anthers 1-1.3 mm long. Female in- 
florescences terminal on new lateral shoots, 2-4 cm long, 
rachis densely stellate-tomentose, pedicles 0.5-2 mm long; 
9 flowers crowded, 5-6 mm long, calyx lobes 2-3 mm 
long, densely stellate-tomentulose on the exterior, ovary 
ca. 3 mm long, densely puberulent, style branches 2 times 
bifid in the proximal half. Fruits not seen. 

Croton axillaris is recognized by its deciduous 
forest habitat, stiff ovate-triangular leaves with 
dense covering of stellate hairs, pinnate venation 
with more than 1 pairs of secondary veins, and 
compact inflorescences. The short-stalked stellate 
hairs have approximately five to seven lateral rays 
and one longer central ray. This species was de- 
scribed from material collected from Granada, 



88 



FIELDIANA: BOTANY 



Nicaragua, and is reported from northwestern 
Costa Rica by Nelson Zamora (pers. comm.). The 
species ranges northward to Guatemala in decid- 
uous forest formations. 

Croton billbergianus Mull. Arg., Linnaea 34: 98. 
1865. C. grosseri Pax, Hot. Jahrb. Syst. 33: 290. 
1903. C. pyramidalisj. D. Smith, Bot. Gaz. 35: 
7. 1903. C. billbergianus ssp. pyrarnidalis (J. D. 
Smith) Webster, Ann. Missouri Bot. Gard. 75: 
1123. 1988. Figure 19. 

Small trees or shrubs 3-1 5 m tall, bisexual, sap yellow 
or orange, leafy stems 2-6 mm thick, scurfy-stellate with 
appressed hairs with 8-20 peripheral rays, 0.2-0.5 mm 
wide; stipules 4-7 mm long, linear, caducous. Leaves 
with petioles 1.6-9(-12) cm long, 0.8-2 mm thick, scurfy- 
stellate, with 2 lateral abaxial sessile saucer-like, patel- 
liform or cupulate glands 0.7-1 .5 mm diam. at the apex; 
leaf blades 9-25(-32) cm long, 4-1 7(-24) cm wide, ovate- 
oblong, to oblong or ovate-elliptic, apex acuminate to 
caudate-acuminate, narrowed tip 4-1 5 mm long, margin 
subentire with minute (0.2 mm) glands along the margin, 
ca. 6-10 glands/cm, base rounded and truncate to cor- 
date with a shallow (0-7 mm) sinus, drying thinly char- 
taceous and often greenish, surfaces with small (0.1-0.3 
mm) stellate hairs and larger hairs along the veins, more 
densely pubescent beneath, glandular punctate, venation 
pinnate or subpalmate, 2 veins 6-1 I/side, basal 2 veins 
sometimes strongly developed. Inflorescences terminal 
or axillary, 1.5-16 cm long, sometimes with 2-4 prox- 
imal branches to 1 1 cm long, bisexual or $, densely stel- 
late, 2 flowers 3-8/rachis, solitary, on pedicels 1-8 mm 
long, 0.8-1.6 mm thick; <5 flowers in glomerules of 3-5, 
pedicels 2-8 mm long. Male flower buds 2.5-3.5 mm 
diam., calyx 34 mm long, lobes 5, ca. 2 mm long, 3.5 
mm wide at base, triangular, petals 3.4-3.8 mm long; 
stamens 13-16, filaments ca. 4 mm long, glabrous dis- 
tally, anthers 1.1-1.5 mm long. Female flowers with 5 
sepals, 3-5.5 mm long, 1.2-3.3 mm wide, glabrous on 
the interior, becoming reflexed, disk with lobes 0.3-0.4 
mm thick; ovary 1.5-2 mm long, 2.3-3 mm diam., stel- 
late-hispid, styles united to form a hispid column 0.5- 
1 mm long, style branches 6-12 (more), 2-4 mm long, 
glabrous distally. Fruits 7-8 mm long, 9-10 mm wide, 
hispid, subtended by the prominent 5-lobed flat disk and 
reflexed calyx, columella 4.5-5.5 mm long; seeds 4.5-5 
mm long, 3.54 mm wide, 3-3.2 mm thick, oblong, ca- 
runcle 0.7-1.5 mm wide. 

Plants of lowland evergreen forest formations 
on both Caribbean and Pacific slopes, 20-800 m 
elevation. Flowering in April-July; fruiting in July- 
December. The species ranges from Veracruz, 
Mexico, to Panama. 

Croton billbergianus is recognized by its yellow- 
orange sap, larger thin ovate-oblong leaves often 
slightly cordate at the base, sessile glands at the 
apex of the petiole, longer anthers, reflexed 2 se- 
pals, thick-lobed disk subtending the ovary, and 
short hispid style column with 1 2 style branches. 



The compound inflorescences, branched near the 
base, are very distinctive but not common among 
the collections seen. Leaves often dry greenish, but 
there is considerable difference in the leaf shape 
of different collections. Nevertheless, the leaves 
are usually more clearly oblong than they are in 
our other large-leaved species. Subspecies pyr- 
arnidalis (Mexico to Honduras) has larger seeds 
and stipules than those found in ssp. billbergianus. 
Compare C. hoffmannii, where the ovary is sub- 
tended by a pubescent disc. 

Croton brevipes Pax, Bot. Jahrb. Syst. 33: 290. 
1903. Figure 12. 

Shrubs or small treelets 1-5 m tall, bisexual, leafy 
stems 0.7-5 mm thick, often with long (ca. 12 cm) in- 
temodes, stellate hairs short-stipitate, ca. 0.6 mm diam., 
with ca. 6-8 rays; stipules 2-6 mm long, subulate. Leaves 
often opposite or subopposite (whorled) at distal or flow- 
ering nodes, petioles 5-48 mm long, 0.7-2 mm thick, 
stellate-pubescent, apex with 2 lateral yellowish glands 
0.5-1.7 mm long, usually narrowly stipitate and saucer- 
like distally, 0.5-1 . 1 mm wide; leaf blades 5-22 cm long, 
2-9 cm wide, elliptic to ovate-elliptic, elliptic-oblong, or 
narrowly obovate, apex acute or acuminate, margin with 
broad rounded teeth 2-4 mm high, 5-8/side, sinuses of 
the margin often with stipitate glands to 1 mm long, base 
obtuse or cuneate and slightly rounded at the petiole, 
drying thinly chartaceous, usually dark above and much 
paler beneath, with scattered small (0. 1-0.6 mm) stellate 
hairs and larger hairs on the veins both above and below, 
venation pinnate, 2 veins 4-8/side. Inflorescences ter- 
minal (pseudoaxillary), solitary, bisexual, 1 .2-5 cm long, 
with 1-3 proximal 2 flowers on short (2 mm) pedicels, 
<? flowers 1-2/bract, pedicels 1-3 mm long. Male flower 
budsca. 1.3 mm diam., sepals 5, stellate-pubescent, 1.2- 
1.7 mm long, petals 1.4-1.8 mm long; stamens 10-12, 
filaments 1.8-2.5 mm long, glabrous, anthers 0.4-0.7 
mm long. Female flowers with sepals 1.7-6 mm long, 1- 
1.5 mm wide, oblong, glabrous within, often with teeth 
on the edge; ovary 1.5-3 mm long, 1.8-3 mm diam., 
glabrous, styles 1-2 mm long, 2 times bifid. Fruits ca. 7 
mm long, 5-6 mm wide, smooth, usually glabrous, sub- 
tended by persisting perianth, columella 3-4 mm; seeds 
3.8-5 mm long, 2.7-3.7 mm wide, 2-2.5 mm thick, 
slightly striate-reticulate, caruncle 0.5-1 mm wide. 

Plants of evergreen forest formations on both 
the Caribbean and Pacific slopes, 20-800 m ele- 
vation. Probably flowering and fruiting through- 
out the year. The species ranges from northern 
Costa Rica to Choco, Colombia. 

Croton brevipes is recognized by the thin serrate 
leaves with pinnate venation, broad rounded teeth, 
and stipitate glands present in some sinuses along 
the leaf margin as well as at the apex of the petiole. 
Long internodes, opposite or whorled leaves at 
some distal nodes, and the short inflorescences are 
additional characteristics. This species is very 



BURGER & HUFT: FLORA COSTARICENSIS 



89 



closely related to C. macrodontus Mull. Arg. of 
Mexico, but there are minor distinctions and the 
two are widely allopatric (cf. Webster & Huft, 
1988). 

Croton decalobus Mull. Arg., Linnaea 34: 80. 1865. 
C. pittieri Pax in Pittier, Prim. Fl. Costar. 2: 
338. Figure 16. 

Shrubs 1-4 m tall, bisexual, much-branched, leafy 
stems 1-4 mm thick, stellate-pubescent with hairs 0.4- 
0.8 mm diam., sessile or on short (0.2 mm) stipes, gla- 
brescent and reddish brown in age; stipules 48 mm long, 
linear. Leaves with petioles 3-18 mm long, 0.8-1.3 mm 
thick, densely stellate-pubescent, lacking glands at or 
near the apex; leaf blades 3-10 cm long, 2-5 cm wide, 
ovate-lanceolate to ovate-triangular or lanceolate, apex 
tapering gradually and acute or acuminate, margin en- 
tire, base acute to rounded or obtuse, drying chartaceous, 
dark above with simple scabrous or stellate hairs ca. 0.3 
mm diam., pale grayish beneath with a dense tomentum 
of stellate hairs with 6-9 rays, venation pinnate, 2 veins 
4 13/side. Inflorescences terminal, 1-3 (rarely more on 
leafless terminal stems), unisexual or bisexual, 3-10 cm 
long, 9 flowers subsessile and with viscous glandular hairs, 
solitary, <3 flowers 1 /bract, pedicels 1-2 mm long (prean- 
thesis). Male flower buds 2.5-3 mm diam., densely short- 
pubescent externally, petals 2-3 mm long, narrowly spat- 
ulate; stamens ca. 1 5, filaments puberulent, anthers 0.7- 
1 mm long. Female flowers ca. 6 mm long, sepals 4-6 
mm long, ca. 1 mm wide, densely short-pubescent abax- 
ially, with distinctive slender gland-tipped hairs along 
the inner margin 0.8-3 mm long; ovary densely pubes- 
cent, style branches ca. 2.5 mm long, pubescent, distally 
bifid. Fruits ca. 5 x 5 mm, columela 3.7^1 mm long, 
reddish, minutely fimbriate or glabrous; seeds 4-5.2 mm 
long, 3-3.4 mm wide, 2.2-2.4 mm thick, smooth and 
lustrous, caruncle 0.8-0.9 mm wide. 

Rarely collected plants of evergreen forest for- 
mations in the central highlands, 1100-1800 m 
elevation. Flowering in June-July; fruiting in July- 
August. This species has been collected only in the 
eastern Meseta Central, from Tibas and Escazu to 
Cartago and Agua Caliente. The species is also 
known from central Honduras and Guatemala. 

Croton decalobus is recognized by its often nar- 
rowly ovate-triangular leaves lacking glands at the 
petiole/blade interface, pinnate venation, and un- 
usual gland-tipped hairs along the inner edge of 
sepals in 9 flowers. The apex of the gland-tipped 
hairs is often elongate, resembling anthers on sta- 
mens. 

Croton draco Cham. & Schldl., Linnaea 6: 360. 
1831. Cyclostigma panamensis Klotzsch in 
Seem., Hot. voy. Herald 105. 1853. Cy. denti- 
culatum Klotzsch in Seem., Bot. voy. Herald 
105. 1853. Cr. panamensis (Klotzsch) Mull. Arg. 



in DC., Prodr. 15 (2): 546. 1866. Cr. steyer- 
markianus Croizat, J. Arnold Arbor. 21: 86. 
1940. Cr. triumfettoides Croizat, J. Arnold Ar- 
bor. 21: 86. 1940. Cr. draco ssp. panamensis 
(Klotzsch) Webster, Ann. Missouri Bot. Gard. 
75: 1120. 1988. Figure 18. 

Trees or shrubs 2-1 5(-30?) m tall, bisexual, leafy stems 
2-8 mm thick, densely pubescent with scurfy or stellate 
hairs 0.2-0.5 mm diam. or with longer slender hairs to 
1 mm; stipules 3-10 mm long (to 12x4 mm in Mexico), 
linear or lanceolate. Leaves sometimes opposite at distal 
nodes, petioles 4.2-14(-20) cm long, 1-3.5 mm thick, 
densely stellate-scurfy, adaxial apex with 2-8 patelliform 
or saucer-like glands 0.4-1 .7 mm wide, sessile or stipitate 
and 0.4-3.5 mm long; leaf blades (7-)l l-26(-30) cm 
long, (4-)6-16(-23) cm wide, ovate-triangular to ovate, 
apex gradually narrowed and acuminate, tip 8-22 mm 
long, margin minutely (0.2-1 mm) denticulate or sub- 
entire, base rounded and truncate to cordate, drying 
chartaceous, dark above with stellate or scurfy hairs to 
0.4 mm diam., grayish beneath with scurfy or stellate 
hairs 0.3-1 mm diam., stellate hairs with 8-14 rays, 
venation palmate or subpalmate with 3 major veins, 2 
veins 4-10/side of the midvein, 3 veins subparallel. 
Inflorescences terminal, bisexual or 3, 7-35(-70) cm long, 
with proximal 9 flowers or cymules with 1 9 flower and 
1-several <5 flowers, or with many cymules of 3-15 6 
flowers, bracteoles 1-1.5 mm long, $ pedicels 1-4 mm 
long, <? pedicels 3-8 mm long, slender. Male flowers 3- 
6 mm wide, calyx ca. 2.2 mm long, calyx lobes 5, 1-2.3 
mm long, triangular, petals ca. 2 x 0.5 mm; stamens 
13-20, filaments 1.5-3 mm long, glabrous, anthers 0.4- 
0.8 mm long. Female flowers densely pubescent exter- 
nally, sepals 5, 1.3-2.5 mm long, 1-1.5 mm wide, gla- 
brous within, petals 1-2 mm long, usually filiform, disc 
inconspicuous; ovary 2.5-4 mm diam., pubescent, styles 
deeply or partly bifid (6/flower), 2.5-3.5 mm long. Fruits 
5-6 mm long, 6-8 mm wide, densely yellowish scurfy- 
stellate, pedunculate, subtended by the closely appressed 
sepals (rarely rotate), columella 3-4 mm long; seeds 3.8- 
5 mm long, 2.4-3.6 mm wide, 2-2.5 mm thick, oblong- 
ellipsoid, with lateral raised ridges (sometimes chevron- 
like), caruncle ca. 2 mm wide. 



Common plants of partly deciduous and ever- 
green forest formations of the central highlands, 
(10-)700-2200 m elevation. Probably flowering 
throughout the year but collected most often in 
June-September. This species is rarely colleced 
below 700 m but was said to be common near 
Golfito (Allen 6627). The species ranges from Ve- 
racruz, Mexico, to Colombia. 

Croton draco is recognized by its larger ovate- 
triangular leaves with as many as 1 2 glands at the 
apex of the petiole, long inflorescences, 6 flowers 
present with proximal 9 flowers in bisexual inflo- 
rescences, pedicellate 9 flowers with relatively small 
calyx lobes and inconspicuous disk, and seeds with 
raised lateral ridges. The $ inflorescences are often 



90 



FIELDIANA: BOTANY 



densely flowered with many closely spaced glom- 
erules of 5-1 1 flowers (distal fascicles may have 
one to a few $ flowers). The complex indument of 
both scurfy and stellate hairs is not found in all 
collections. Targud and copalchi are common 
names applied to this and similar Croton species. 
This species is similar to C. xalapensis and C. 
hoffmannii in general appearance, but the latter 
two species do not have <5 and 2 flowers together 
in the same glomerules. 

Croton glandulosus L., Syst. ed. 10. 1275. 1759. 

Herbs, erect or decumbent, to 0.6 m tall, bisexual, 
leafy stems 1-2.5 mm thick, with appressed stellate hairs 
0.4-1.3 mm wide; stipules to 0.5 mm long, gland-like 
or absent. Leaves often opposite below branching nodes, 
petioles 2-9 mm long, ca. 0.6 mm thick, densely stellate- 
pubescent, with paired lateral subsessile glands at apex, 
ca. 0.5 mm diam.; leaf blades 7-35 mm long (larger in 
the northern part of its range), 6-16 mm wide, broadly 
ovate to ovate-elliptic or narrowly oblong, apex rounded, 
margin crenate with 3-5 rounded teeth/cm, base obtuse 
to truncate, drying grayish green, stellate-pubescent above 
and beneath, venation pinnate or subpalmate. Inflores- 
cences terminal and pseudoaxillary, to 2 cm long and 5 
mm wide, developing 2-4 fruits/node; <3 flowers with 7- 
1 3 stamens; 9 flowers with deeply bifid styles (appearing 
as 6). Fruits 4-5 mm long, splitting at the apex but often 
remaining united beneath, covered with thin stellate hairs 
ca. 0.8 mm wide, columella ca. 3 mm long, slender; seeds 
ca. 3 mm long, 2-2.5 mm wide, oblong, lustrous. 

Croton glandulosus is recognized by the short 
herbaceous habit, thin stellate-appressed hairs, 
small leaves with prominent rounded teeth, sub- 
sessile saucer-shaped glands at the apex of the pet- 
ioles, and short inflorescences. Standley (1937) re- 
ported this species from Cost Rica, but we have 
seen no material from southern Central America. 
The species ranges from the southeastern United 
States, Mexico, and the West Indies to South 
America. 

Croton hirtus L'Her., Stirp. Nov. 17, t. 9. 1785. 
C. glandulosus L. subsp. hirtus (L'Her.) Croizat, 
Bull. Torrey Dot. Club 75: 401. 1948. Figure 10. 

Annual herbs 20-90 cm tall, bisexual, leafy stems 0.8- 
6 mm thick, hispid with stellate hairs having small (0.3- 
0.7 mm) thin basal rays and 1 central ray 2-3.5 mm 
long, often dense and retrorse; stipules 2-4.5 mm long, 
ca. 0.5 mm wide, linear, pubescent. Leaves with petioles 
3-30 mm long, 0.3-1 mm thick, with thin stellate hairs 
to 2 mm long, with paired (1-4) stalked yellowish glands 
0.5-1.2 mm long near the apex; leaf blades 1.3-9 cm 
long, 0.9-5.8 cm wide, ovate to ovate-triangular or ovate- 
oblong, apex acute to rounded, margin with 10-25 
rounded teeth/side, base rounded and truncate to broad- 



ly obtuse, drying thinly chartaceous, greenish to yellow- 
brown, upper surface with thin simple hairs 0.3-1 mm 
long, lower surface stellate with small (1 mm diam.) and 
longer (2 mm) hairs along the veins, venation palmate 
with 3 major veins, 2 veins 1-4/side of midvein. Inflo- 
rescences terminal, 1-3, bisexual, 1-10 cm long, often 
subtended by small leaves, peduncles 0-28 mm long, ca. 
0.5 mm thick, stellate-pubescent, 9 flowers 3-12, sub- 
sessile, 3 flowers 4-9, pedicels 1-3 mm long, slender, 
rachis with gland-tipped hairs and linear bracts with 1- 
3 slender gland-tipped segments 0.5-5 mm long. Male 
flower buds ca. 1.8 mm diam., densely pubescent exter- 
nally, sepals 5, 1-1.5 mm long, stellate externally; sta- 
mens 8-1 2, filaments 0.8- 1.5 mm long, glabrous, anthers 
0.3-0.5 mm long. Female flowers with 4 unequal sepals 
3.5-4 mm long, 0.5-1 mm wide, oblanceolate to linear, 
pubescent; ovary ca. 3 x 2 mm, styles separate above 
the base, 1.5-2.5 mm long, bifid. Fruits ca. 4 mm long, 
3.5-4.5 mm wide, stellate-pubescent (glabrous), sepals 
to 6 mm long, columella 2.8-3.2 mm long; seeds 2.8- 
3.6 mm long, 2-2.8 mm wide, 1 .4-1 .8 mm thick, oblong- 
lenticular, smooth with surface minutely reticulate, lus- 
trous, caruncle ca. 1.5 mm wide. 

Weedy plants of open sunny sites in evergreen 
and deciduous areas, 0-1700 m elevation. Flow- 
ering and fruiting material has been collected 
mostly in March-August in southern Central 
America. In Costa Rica, it is most often collected 
on the Pacific slope and lowlands below 1200 m 
elevation. The species ranges from Mexico to Bra- 
zil, mostly in deciduous vegetation. 

Croton hirtus is recognized by its annual weedy 
habit, distinctive (usually retrorse) pubescence, 
stipitate glands at base of the blade (often difficult 
to see or absent), simple hairs on upper leaf sur- 
faces, and short inflorescences with unusual bracts 
with slender segments that resemble gland-tipped 
hairs. The stellate hairs of the stem, with a basal 
circle of short thin rays and a central erect large 
ray, are distinctive, but the small basal rays are 
often difficult to see. Material of this species was 
often placed under Croton glandulosus, but that 
species lacks the unusual hispid hairs and has ses- 
sile petiolar glands and floral bracts without glands. 

Croton hoffmannii Mull. Arg., Linnaea 34: 86. 
1 865. C. hoffmannii var. incana Mull. Arg., Lin- 
naea 34: 86. 1865. C. hoffmannii var. viridis 
Mull. Arg., Linnaea 34: 86. 1865. Oxydectes tur- 
rialva O. Ktze. and C. turrialva O. Ktze. (as 
syn.), Rev. gen. 2: 614. 1891. Figure 19. 

Shrubs or small trees 1 . 5-6 m tall, bisexual, leafy stems 
2-6 mm thick, densely stellate-pubescent with short- 
stipitate (0.1-0.8 mm) hairs 0.3-0.7 mm diam.; stipules 
5-7 mm long, linear, caducous. Leaves sometimes op- 
posite at distal flowering nodes, petioles 2-15 cm long, 
1-3 mm thick, densely stellate-pubescent, usually with 



BURGER & HUFT: FLORA COSTARICENSIS 



91 



2 latcral/abaxial saucer-like or patelliform sessile glands 
near the apex, 0.7-1.3 mm wide; leaf blades 7-22 cm 
long, 4-19 cm wide, ovate to ovate- triangular, acute to 
acuminate at the apex, margin minutely dentate with 
small (0.3-1 mm) gland-tipped teeth, ca. 3-9 teeth/cm, 
base rounded and cordate to truncate, drying thinly char- 
taceous, upper surface with simple or stellate hairs, lower 
surface more densely pubescent, stellate hairs with 8-14 
rays, 0.3-0.7 mm diam., venation palmate or subpal- 
mate with 3 prominent veins from base, 2 veins 3-87 
side of midvein. Inflorescences 8-30 cm long (often pen- 
dulous in life), terminal, 1-4, usually bisexual with 1- 
1 2 proximal solitary 2 flowers or proximal cymules with 
1 2 and 2 6 flowers, flowers or fascicles usually distant 
along the rachis, 2 pedicels 1-2 mm long, $ pedicels 1- 

3 mm long, distal bracts to 6 mm long subtending 3-9 
6 flowers. Male flower buds ca. 3 mm diam., calyx ca. 

4 mm long, calyx lobes 1-2.5 mm long, 1.5-2.7 mm 
broad at base, petals 5, ca. 3 mm long; stamens ca. 16, 
anthers 0.7-0.8 mm long. Female flowers ca. 6-7 mm 
long, calyx lobes 5, unequal and imbricate in bud, 3-4 
mm long, 1.5-5 mm broad, triangular to ovate, glabrous 
within, disk with dense radiating hairs 0.7 mm long; 
ovary densely hirsute, ca. 3 mm diam., styles with short 
(0.5 mm) pubescent column, each style with 4 glabrous 
branches ca. 3 mm long. Fruits ca. 8 x 10 mm, sub- 
tended by the rotate or reflexed sepals, columella 6-7.5 
mm long; seeds 6-8 mm long, 4.3-5 mm wide, 3.2-4 
mm thick, smooth or with some irregular raised areas, 
caruncle 2.6-3 mm wide. 

Plants of open weedy sites in evergreen forest 
formations 900-1600 m elevation. Flowering in 
June-August; fruiting in October-December. In 
Costa Rica, this species appears to be restricted to 
the area between the eastern part of the Meseta 
Central and the northern edge of the Cordillera de 
Talamanca (Rio Virilla eastward to the Orosi val- 
ley). Specimens determined as this species have 
also been collected in Mexico. 

Croton hoffmannii is recognized by its larger 
ovate-triangular leaves with sessile glands at the 
apex of the petiole, serrulate margins, long inflo- 
rescences with uncrowded flowers, larger 2 flowers 
with ovary subtended by a densely pubescent disc 
(easily seen in fruit because of the rotate or reflexed 
sepal lobes), larger seeds, and very limited geo- 
graphic range. Some inflorescences have proximal 
cymules with 1 2 flower and 2 $ flowers. The leaves 
are often ovate-triangular and usually dry yellow- 
ish green. The calyx is united almost 50% in both 
$ and 2 flowers. The restricted flowering period, 
flowers well separated along the inflorescence ra- 
chis, and calyx united to form clearly visible cups 
help distinguish this species from the vegetatively 
similar C. draco, C. pungens, and C. xalapensis. 

Croton jimenezii Standl. & Valerio, Publ. Field 
Mus. Nat. Hist., Bot. Ser. 18: 604. 1937. Figure 
19. 



Trees or shrubs, 3-15 m tall, bisexual or unisexual, 
leafy stems 2-8 mm thick, densely pubescent with short 
(0.2 mm) reddish brown scurfy-stellate hairs ca. 0.3 mm 
wide at the flattened apex, the hairs often with slender 
central rays to 1.5 mm long; stipules 3-5 mm long, 0.5- 
2 mm wide at base, pubescent, caducous. Leaves with 
petioles 3.6-14.5 cm long, 0.8-3.5 mm thick, densely 
brownish scurfy-stellate hirsutulous, often contracted at 
apex and base when dried, apex with 2-5 glabrous stip- 
itate conical glands 0.5-1 .5 mm long, 0.4 mm wide; leaf 
blades 8-24 cm long, 413 cm wide, ovate to ovate- 
triangular or ovate-oblong, apex acuminate with narrow 
tip 6-14 mm long, margin entire or subentire (glandular- 
crenate), base rounded and truncate or subcordate, dry- 
ing chartaceous, upper surface with scurfy-stellate hairs 
ca. 0.2 mm wide, lower surface with similar hairs 0.2- 
0.4 mm wide, hairs to 2 mm long sometimes present 
near base and along midvein, venation pinnate or sub- 
palmate, 2 veins 7-10/side. Inflorescences terminal, 
usually solitary, unisexual or bisexual, 4-30 cm long, ca. 

2 cm wide, peduncle 2-3.5 mm thick, pubescent as the 
stems, bracts 0.7-3 mm long, subtending 1 subsessile 2 
flower or 1-56 flowers on pubescent pedicels 2.5-6 mm 
long, 0.2-0.4 mm thick. Male flower 5-10 mm wide at 
anthesis, pubescent externally, calyx lobes 1.5-2.5 mm 
long, petals 2-3 mm long; stamens 21-31, filaments ca. 

3 mm long, pubescent only at the base, anthers 0.6-0.8 
mm long. Female flowers pubescent externally, calyx lobes 
5, 3-1 1 mm long, 1-3 mm wide, spathulate to oblong; 
ovary ca. 3 mm diam., covered with many-pointed stel- 
late hairs 0.5-1 mm wide, styles 3-4 mm long, undivided 
for ca. 1 mm, twice bifid (12 distal parts). Fruits ca. 6 
mm long (only 1 seen); seeds 3.7-5 mm long, 3-4 mm 
wide, ca. 2 mm thick, oblong-lenticular, surface smooth 
or very slightly rugulose, caruncle 0.8-2 mm wide. 



Trees of wet evergreen montane forests near the 
continental divide of the central volcanic high- 
lands and Cordillera de Talamanca, (1000-)! 500- 
2500 m elevation. Flowers have been collected in 
December-May and July. This endemic species 
ranges from near Zarcero eastward to Sta. Cruz de 
Turrialba and is also known from a single collec- 
tion from along the Inter- American Highway about 
27 km north of San Isidro del General. 

Croton jimenezii is recognized by the dense pu- 
bescence of brownish or yellowish stellate/scurfy 
hairs, larger ovate-triangular leaves, oblong 2 calyx 
lobes that enlarge as the fruit develops, $ flowers 
with 21-30 stamens, and restricted montane hab- 
itat. The hairs of the stems often have very short 
(0.1 mm) stalks and a flattened reddish brown 
distal portion with short marginal teeth, giving a 
rufous scurfy-stellate appearance. In addition, the 
hairs often have one transparent central ray be- 
coming 1-2 mm long. Though little collected, the 
species has been noted as locally common and 
called targua. Collections with only $ flowers may 
be very difficult to separate from C. draco. 



92 



FIELDIANA: BOTANY 



Croton jutiapensis Croizat, Publ. Field Mus. Nat. 
Hist., Bot. Ser. 22: 450. 1942. Figure 16. 

Small shrubs 0.5-1 (-2) m tall, bisexual, leafy stems 
0.7-3 mm thick, stellate-pubescent with hairs ca. 0.5 mm 
diam., sometimes with longer rays 0.5-1.5 mm long, 
whitish or yellowish, glabrescent and dark in age; stipules 
3-8 mm long, linear, caducous. Leaves with petioles 3- 
12(-32) mm long, 0.4-1.3 mm thick, densely stellate- 
pubescent, with 2 (3-4) lateral/abaxial stipitate conical 
yellowish glands 0.4-1 m long, 0.2-0.7 mm wide at apex; 
leaf blades 1.7-9(-l 1) cm long, 0.8^t.3(-5.5) cm wide, 
ovate-triangular to ovate-lanceolate or ovate-elliptic, apex 
acute or acuminate, margins with 7-19 short (0.5-2 mm) 
teeth/side, base cuneate to rounded and subcordate, dry- 
ing chartaceous, upper surface usually dark with stellate 
hairs ca. 0.5 mm diam., lower surface densely stellate 
and pale colored, venation pinnate or subpalmate, 2 
veins 3-8/side. Inflorescences terminal or axillary, sol- 
itary, 2-5(-7) cm long, usually bisexual, peduncles 5-15 
mm long, densely stellate-pubescent, 9 flowers 1-7, sub- 
sessile or short pedicellate, $ flowers solitary, pedicels 
ca. 2 mm long, bracteoles 1-3 mm long, linear. Male 
flower buds ca. 2 mm diam., sepals 5, 1-2 mm long, 
0.8-1 mm wide, triangular, petals 5, 1.7-2.2 mm long, 
ca. 1.1 mm wide, oblong to spathulate; stamens ca. 1 1, 
filaments 1.5-3.5 mm long, glabrous, anthers 0.4-0.7 
mm long. Female flowers 3.5-8 mm long, sepals 1.5-5 
mm long, becoming 5-8 mm long in fruit, subequal or 
unequal; ovary ca. 3 x 4 mm, densely stellate-hispid, 
styles 24 mm long, bifid to the base (6). Fruits 4.5-6 
mm long, densely hispid, columella 3-4 mm long; seeds 
3.3-4 mm long, 2-3.3 mm wide, 1.5-1.8 mm thick, ob- 
long-ellipsoid, smooth, lustrous, caruncle 0.8-1.8 mm 
wide. 

Common plants in open sunny sites in season- 
ally dry deciduous woodland formations, 0400 
m elevation (to 1 1 00 m in Honduras and Gua- 
temala). Flowering in April-August; fruiting in 
July-October. The species ranges from the Peten 
area of Guatemala along the Pacific slope to Guan- 
acaste Province in Costa Rica. 

Croton jutiapensis is recognized by the short- 
shrubby habit with older stems becoming blackish 
and glabrous, seasonally dry habitat, leaves usu- 
ally ovate-lanceolate with lateral stipitate glands 
near the apex of the petiole, pinnate venation, and 
short inflorescences. Many Costa Rican collec- 
tions have been identified as C. costaricensis, but 
that name is a synonym of C. ortholobus, a species 
of higher elevation. 

Croton lanjouwensis Jabl., Mem. New York Bot. 
Gard. 12: 158. 1965. C. matourensis Abulet var. 
benthamianus Mull. Arg., Linnaea 34: 95. 1865. 
C. benthamianus (Muell. Arg.) Lanjouw. Eu- 
phorb. Surinam 17. 1931, non C. benthamianus 
Mull. Arg. in Mart., Fl. Bras. 1 1 (2): 106. 1874. 
Figure 17. 



Trees 7-40 m tall, bisexual, leafy stems 1-6 cm thick, 
covered with flat rounded-appressed peltate hairs 0.3- 
0.5 mm diam. and yellowish brown dried; stipules 6-10 
mm long, ca. 1.2 mm wide at base, covered with peltate 
hairs, caducous. Leaves with petioles 11-55 mm long, 
0.7-1.7 mm thick, covered with peltate scales, with 2 
adaxial lateral patelliform glands 0.7-1.6 mm wide at 
the apex; leaf blades 7- 1 6 cm long, 3-6 cm wide, elliptic- 
oblong to oblong or elliptic, apex acute to short-acu- 
minate with tip 3-8 mm long, margin entire, base acute, 
drying stiffly chartaceous, dark brown to grayish brown, 
glabrous above, sparsely to covered beneath with peltate 
hairs 0.3-0.4 mm diam., venation pinnate with 1 1-22 
veins/side. Inflorescences terminal, 1-4, 6-18 cm long, 
racemose, bisexual, peduncles 12-60 mm long, ca. 2 mm 
thick, with peltate hairs, with 1-6 proximal 9 flowers on 
pedicels to 5 mm long (to 1 5 mm in fruit), 3 flowers in 
distal groups of 3-5, bracts 1-4 mm long, lepidote. Male 
flower buds ca. 2 mm diam., covered with peltate hairs, 
calyx lobes 5, valvate, 2-2.5 mm long, petals to 2 mm 
long; stamens ca. 12, anthers 0.6-0.7 mm long. Female 
flowers ca. 6 mm long, 8-10 mm wide, calyx lobes 5, 3- 
4.5 mm long, triangular, valvate, with stellate hairs on 
the inner surface and peltate externally, petals absent; 
ovary ca. 3.5 mm diam., styles ca. 4 mm long, twice 
bifid. Fruits (not seen) ca. 5 mm long, columella ca. 4 
mm long; seeds ca. 3.5 mm long, rounded. 

Trees of wet evergreen rain forest formations on 
the Caribbean slopes between 200 and 800 m el- 
evation. Flowering in March and July in southern 
Central America. This species ranges from near 
the Costa Rican-Panama border to the eastern 
Amazon Basin. 

Croton lanjouwensis is recognized by its large 
stature, flat rounded-appressed peltate hairs cov- 
ering many surfaces, paired glands at the apex of 
the petioles, pinnate venation with many second- 
ary veins, and larger 9 flowers. We have seen only 
a single Costa Rican collection (A. Chacon 182 CR, 
F, MO) from 800 m elevation in Parque Interna- 
cional La Amistad. The large height attained by 
these trees may explain why they are not collected 
more often. This species is closely related to C. 
matourensis Aublet of South America. 



Croton lobatus L., Sp. PI. 1005, 1 753. Astraea see- 
mannii Klotzsch in Seem., Bot. voy. Herald 103, 
1853. C. lobatus var. seemannii (Klotzsch) Mull. 
Arg. in DC., Prodr. 15 (2): 669. 1866. Figure 2. 

Herbs 0.2-0.9(-1.5) m tall, bisexual, often with distal 
leaves and shoots from congested nodes, leafy stems 1- 
4.5 mm thick, with sessile-stellate hairs 0.3-1 .8 mm long 
or with only 1 ray of the hair developing and simple; 
stipules 2-6 mm long, 0.5-0.8 mm broad at base, lan- 
ceolate to linear (sometimes deeply split and more than 
2/node). Leaves with petioles 3-11 cm long, 0.4-1 .3 mm 
thick, sparsely puberulent with mostly simple hairs to 2 
mm long, with minute lobed or digitate glands 0.1-0.4 



BURGER & HUFT: FLORA COSTARICENSIS 



93 



mm long at the adaxial apex; leaf blades 3-9 cm long, 
2-10 cm wide, 3-5-lobed with deep narrow sinuses (or 
unlobed and lanceolate), central lobe elliptic to oblan- 
ceolate, apices acuminate, margins of the major lobes 
with 1 2-20 teeth/side, base truncate to subcordate, dry- 
ing thinly chartaceous, greenish to brown, with mostly 
simple hairs 0.3-1 mm long above and below, venation 
palmate with 3-5 veins (unlobed leaves pinnately veined 
with ca. 5 veins/side). Inflorescences terminal, 2-6(-15) 
cm long, racemose, bisexual with l-3(-7) proximal sol- 
itary 9 flowers and 4-12 distal <5 cymules, bracts ca. 2 
mm long below 9 flowers and 1 mm long below 3 flowers, 
9 pedicels ca. 1 mm long and densely pubescent, to 3 
mm long in fruit; <5 flowers solitary or in cymules of 2- 
5, 6 pedicels ca. 2 mm long and glabrous. Male flower 
buds ca. 1.2-1.8 mm diam., globose, calyx lobes 5, ca. 
1 . 1 mm long, imbricate and rounded, petals 1 .2-1 .5 mm 
long, 0.5-1 mm wide; stamens (8-)12-15, filaments to 
1 mm long, glabrous, anthers ca. 0.3 x 0.4 mm. Female 
flowers 4-5 mm long, sepals 5, 4-7 mm long, 1-2 mm 
wide, oblanceolate to spatulate, sparsely pubescent, with 
minute teeth or stalked glands near the base, disc of 5 
segments ca. 0.3 mm long; ovary 3-4 mm long, pubes- 
cent with stellate or simple hairs (rarely glabrous), styles 
2-4 mm long, 2 times bifid in the distal half. Fruits ca. 
6 mm long, 6 mm diam., oblong, 3-lobed, columella 4 
5 mm long; seeds 4.5-5.5 mm long, 2.7-3.5 mm wide, 
2.5-3 mm thick, oblong-rectangular, slightly rugulose 
with slanted transverse ribs, caruncle 1.4-2 mm wide, 
reniform-peltate. 

Plants of open sunny sites in lowland evergreen 
to deciduous formations, 0-800 m elevation (in 
Central America). Often found in sandy stream- 
sides or in weedy fields and roadsides. Probably 
flowering and fruiting primarily in the wet season, 
May-December. Though weedy and wide-rang- 
ing, this species is infrequently collected in Central 
America; it has been collected only a few times in 
the Pacific lowlands of central and northern Costa 
Rica (20-350 m). It ranges from Florida and the 
Bahamas to Peru and Brazil and is found in west- 
ern and northeastern Africa. 

Croton lobatus is distinguished by its short weedy 
habit, deeply lobed leaves, leaf surfaces with most- 
ly simple hairs, 9 flowers with five to seven long 
narrow sepals, and unusual seeds. No other species 
of Croton in Costa Rica has leaves with compa- 
rably deep sinuses. 

Croton mexicanus Mull. Arg., Linnaea 34: 113. 
1865. Figure 16. 

Trees 4-15 m tall, bisexual, leafy stems 1.5-4 mm 
thick, stellate-pubescent with flat appressed somewhat 
peltate hairs 0.2-0.4 mm diam., stems becoming grayish 
or reddish brown; stipules 3-4 mm long, linear. Leaves 
with petioles 15-58 mm long, 0.8-2 mm thick, ap- 
pressed-pubescent with stellate or peltate-like hairs, 2 
lateral glands present near the apex of the petiole, 0.7- 
1.5 mm long, 0.4-0.7 mm diam. at apex, conical-cu- 



pulate; leaf blades 5-14(-16) cm long, 2-7 (-9) cm wide, 
ovate-elliptic to narrowly ovate, lanceolate or elliptic, 
tapering gradually to the acute or acuminate apex, mar- 
gin minutely dentate with glandular teeth 0.2-0.4 mm 
high, 3-5 teeth/cm, base cuneate to rounded, drying 
chartaceous, darker above with sparse stellate-peltate 
hairs 0.1-0.4 mm diam., paler and more densely pu- 
bescent beneath with larger hairs, venation pinnate or 
subpalmate with basal 2 veins usually reaching the mid- 
dle of the blade, 2 veins 3-6/side of midvein. Inflores- 
cences terminal, 1-4, unisexual (rarely with bisexual 
glomerules), 2-13 cm long, 9 flowers 1-3, 9 pedicels 1.3- 
3.5 mm long, 1.2-1.5 mm thick, bracteoles ca. 1 mm 
long, <3 flowers in glomerules of 2-5 or solitary, stellate- 
pubescent, 3 pedicels 2-8 mm long, slender. Male flower 
buds ca. 3 mm diam., calyx lobes 5, 1.5-2 mm long, 1.3 
mm wide, petals 5, ca. 2 mm long; stamens ca. 14-16, 
anthers 0.6-0.9 mm long, almost as wide. Female flowers 
with 5 calyx lobes 2.5-3 mm long, ca. 1.3 mm wide; 
ovary 2.3-2.7 mm long, 2-3.3 mm diam., densely stel- 
late-pubescent, style branches pubescent in the lower 
half, glabrous and bifid in the distal half (6). Fruits 10- 
12 mm long, 9-10 mm wide, with stellate-scurfy hairs, 
columella ca. 8 mm long; seeds 6-7 mm long, 4.5-4.8 
mm wide, 2.5-3.2 mm thick, surface smooth but with 
irregular raised areas, caruncle 2-2.7 mm wide. 

Plants of evergreen forest formations on the Pa- 
cific slope and continental divide of the Cordillera 
de Tilaran, 1400-1600 m elevation. Flowering in 
February and June-October; fruiting in August- 
November. The preceding description is based on 
material collected from the area around the Mon- 
teverde community and Cloud Forest Reserve in 
the Cordillera de Tilaran. The material placed here 
appears to be a disjunct population of a species 
otherwise only known from Mexico. 

Croton mexicanus is recognized by its long pet- 
ioles with two prominent glands near the apex, 
narrowly ovate-elliptic leaves with prominent bas- 
al 2 veins, appressed flat-stellate or scurfy pubes- 
cence on many parts, stamens 14 16/flower, and 
slightly rugose seed surfaces. The distally flattened 
stellate hairs with more than 1 5 radiating periph- 
eral rays are distinctive and often have a raised 
brownish center. The rays may be united near the 
elevated center and somewhat peltate, but more 
three-dimensional irregularly stellate (scurfy) hairs 
may also be present. The trees are often conspic- 
uous because of the silvery undersides of their 
leaves. Despite the restricted area from which our 
collections have been made, the Monteverde ma- 
terial exhibits considerable variation; one collec- 
tion has spikes with bisexual glomerules (Haber & 
Zuchowski 10714). Placement of this material un- 
der C. mexicanus is tentative; we have seen no 
authentic material of C. mexicanus. Croton oer- 
stedianus Mull. Arg. is also closely related but has 
leaves that are bluntly retuse at the apex and grows 



94 



FIELDIANA: BOTANY 



at lower elevations in Honduras and Nicaragua. 
Collections placed here were earlier determined 
and distributed as C. monteverdensis, an unpub- 
lished name. 

Croton niveus Jacq., Enum. pi. syst. 32. 1760. Fig- 
ure 17. 

Shrubs or small trees 2-1 2(-20?) m tall, bisexual, leafy 
stems 1.5-4.5 mm thick, whitish, covered with flat 
rounded peltate hairs 0.2-0.4 mm diam., usually with a 
small brown center and whitish circumference; stipules 
3-9 mm long, linear, caducous. Leaves with petioles 7- 
32 mm long, 0.7-1 .8 mm thick, with peltate hairs, glands 
absent near the apex; leaf blades 3-14 cm long, 2-10 cm 
wide, broadly ovate to ovate-orbicular or ovate-trian- 
gular, tapering gradually to an acuminate or acute apex, 
margin serrate to subentire, base rounded and truncate 
to obtuse, drying chartaceous, upper surface dark and 
glabrous or with scattered peltate hairs, lower surface 
grayish or silvery with a dense covering of peltate hairs 
0.2-0.5 mm diam., venation palmate or subpalmate, 
with prominent basal lateral veins, 2 veins 3-5/side of 
midvein. Inflorescences usually axillary, 2-1 1 cm long, 
bisexual or $, with peltate hairs throughout, with 1-3 
proximal 9 flowers on pedicels 4-18(-28) mm long, 0.4- 
1 .7 mm thick, distal bracts 0.5-1 .5 mm long, subtending 
solitary $ flowers on pedicels 1-6 mm long, ca. 0.6 mm 
thick. Male flower buds 2-3 mm diam., sepal lobes 1.3- 
2.2 mm long, triangular, petals 2-3 mm long, ca. 1 mm 
wide, narrowly oblong, with densely ciliolate edge and 
glabrous surfaces; stamens 10-1 5, filaments 2.2-3.3 mm 
long, glabrous, anthers 0.6-1 .3 mm long. Female flowers 
with sepals 2.5-4 mm long, 2.1-3 mm wide at base, 
petals 1-3 mm long, 1.2 mm wide, narrowly oblong, 
with a densely ciliolate white edge; ovary 2.5-5 mm long, 
2.5-5 diam., covered with stellate-peltate hairs, styles 
2.5-3 mm long, bifid to multifid distally. Fruits 9-24 
mm long, 9-20 mm wide, differing greatly in size in 
different collections, usually becoming covered with short 
projections terminating with irregular stellate hairs, col- 
umella 7.5-16 mm long; seeds 6.5-16 mm long, 5.3-1 1 
mm wide, 3-5 mm thick, oblong, dark brown mottled 
with white or yellowish brown, caruncle 1.5-2.2 mm 
wide. 

Plants often seen in hedgerows and roadsides in 
deciduous and partly deciduous forest formations 
(rare in evergreen areas), 50-1800 m elevation. 
Flowering material has been collected in March- 
August and November-December. The species (in 
a wide sense) ranges from Mexico to Venezuela. 

Croton niveus is recognized by the flat appressed 
rounded peltate hairs on almost all outer surfaces, 
ovate-triangular leaves often with silvery under- 
surfaces, and larger fruits and seeds. The hairs 
covering the ovary are usually more stellate (with 
deeply divided rays) than hairs on other surfaces, 
and they often become raised on projections as the 
fruit develops (but see below). This species is often 
used as a hedgerow plant. Dried leaves and bark 



have been used in Guatemala for medicinal pur- 
poses (Standley & Steyermark, 1949, pp. 73, 79). 
The common names copalchfand quisarrd copal- 
c/ are said to be based on the Mayan name copal- 
C/H? (Pittier, 1957, p. 59). 

Cultivation and use by indigenous peoples over 
many centuries may account for the great variation 
in fruit and seed size seen in different collections. 
For this reason, we prefer a broad interpretation 
of this species. The senior author at first included 
C. reflexifolius H.B.K., C. eluterioides Lotsy, and 
C. guatemalensis Lotsy as synonyms under this 
species. However, a reviewer pointed out that these 
species have peltate hairs on the ovary, not stellate 
hairs as in C. niveus (sensu stricto). There are a 
few specimens in which the ovary is covered with 
hairs that appear intermediate between peltate and 
stellate. It is on the basis of such collections that 
it seems likely a broader interpretation of C. niveus 
will prove more useful. The reader should note 
that the material placed under this name may rep- 
resent a complex of closely similar species. 

Croton ortholobus Mull. Arg., Flora 55: 9. 1872. 
Oxydectes costaricense Kuntze, Rev. gen. 2:614. 
1891. C. costaricensis Pax in Pittier, Prim. Fl. 
Costar. 2: 331. 1900. Figure 16. 

Small shrubs 0.5-2.5 m tall, bisexual, leafy stems 0.9- 
4 mm thick, densely stellate-pubescent and apparently 
hispid with central sharp rays to 2.2 mm long, older 
stems glabrescent and dark reddish brown or black; stip- 
ules 2-5(-9) mm long, 0.2-0.4 mm wide, linear, drying 
dark, deciduous. Leaves with petioles 4-30(-52) mm 
long, 0.5-0.9 mm thick, stellate-pubescent and hispid, 
with paired stipitate-cupulate glands at leaf base beneath, 
0.5-1.5 mm long, 0.4-0.7 mm diam. at apex, yellow, 
glabrous; leaf blades 1.8-9.4 cm long, 1.3-5.3 cm wide, 
ovate to elliptic-ovate, apex acute to shortly cuspidate- 
acuminate, margin subentire or minutely (0.5 mm) den- 
ticulate with 8-20 teeth/side, base obtuse to rounded, 
thinly to stiffly chartaceous, upper surface with simple 
or stellate hairs 0.2-1 mm long, lower surface stellate- 
pubescent with hairs 0.3-0.6 mm wide, venation pinnate 
or subpalmate, 2 veins 3-5/side. Inflorescences termi- 
nal, <3 or bisexual, 2-12 cm long, proximal 2 flowers 1- 
12, distal part of spike 1-1.7 cm diam., <5 flowers 
1/bracteole, pedicels 2-3 mm long, slender, bracteoles 
2-4 mm long, linear, often with glands. Male flower buds 
2-2.5 mm diam., calyx lobes 1.5-2 mm long, triangular 
to ovate, pubescent externally, petals 1.8-2.5 mm long, 
spathulate to narrowly obovate; stamens 9-11, filament 
2-3 mm long, glabrous, anthers 0.5-0.9 mm long. Fe- 
male flowers ca. 6 mm long, calyx lobes 2.5-5 mm long, 
ca. 1.3 mm wide, narrowly triangular, petals subulate or 
absent, ovary globose, pubescent, styles deeply bifid. 
Fruits 5.5-6 mm long, 4.5-5.5 mm diam., rounded-ob- 
long, densely pubescent; seeds ca. 4.2 mm long, 2.8-3.2 
mm wide, 1.5-2 mm thick, oblong, smooth, lustrous, 
caruncle ca. 1.5 mm wide. 



BURGER & HUFT: FLORA COSTARICENSIS 



95 



Plants of secondary growth in evergreen lower 
montane forest formations, 1300-2100 m eleva- 
tion. Flowering and fruiting collections have only 
been made in June-August and November. The 
species is only known from the northeastern part 
of the Meseta Central, from near Grecia and Zur- 
qui eastward to Cartago and Paraiso. 

Croton ortholobus is recognized by its short 
shrubby habit, paired stipitate yellowish glands at 
the apex of the petiole (mostly abaxial side), leaf 
blades often with simple hairs above and stellate 
hairs beneath, very restricted geographic range, 
and limited flowering period. The sharp hispid 
hairs of stems and petioles are actually the central 
rays of stellate hairs with much smaller basal/lat- 
eral rays. The type (Friedrichsthall 1417 G, photo 
F) was mislabeled as coming from Guatemala; it 
was collected near Cartago. The name C. costa- 
ricensis has been used for this species and also 
misapplied to collections of C. jutiapensis from 
lowland Guanacaste. 



ca. 2 mm thick, oblong, lustrous, grayish yellow, caruncle 
ca. 1 mm wide. 



Uncommon plants of open sites in seasonally 
very dry deciduous areas, 20-300 m elevation (0- 
1 200 m in South America). Flowering and fruiting 
material was collected in July ( Webster et al. 12475 
F) and August ( Wilbur 31 130 F) in Costa Rica. The 
species appears to range disjunctly from Oaxaca, 
Mexico, and the West Indies to Colombia and 
Venezuela. 

Croton ovalifolius is distinguished by its small 
stature, small leaves, stellate pubescence, unusual 
stipules, and $ sepals. The stipules, bracteoles, and 
9 sepals have a similar glabrous texture (drying 
smooth and brown) that suggests succulence in life, 
and all have distinctive gland-like teeth (with or 
without distal knobs) along the margins. The North 
American material usually has broader leaves, and 
the larger seeds lack the longitudinal striations 
characteristic of South American material. 



Croton ovalifolius Vahl in H. West, Bidr. Beskr. 
Ste. Croix 307. 1793. C. escathos Croizat, J. 
Arnold Arbor. 21: 79. 1940. Figure 10. 

Herbaceous subshrubs 20-90 cm tall, bisexual, leafy 
stems 0.6-2 mm thick, hairs stellate, 0.5-1.5 mm wide 
with slender rays or partly stellate with a single long (1- 
2.3 mm) ray; stipules 1-2.5 mm long, 0.1-0.6 mm wide, 
usually lacking stellate hairs and with several glandular 
teeth along the margin, drying brown, caducous. Leaves 
with slender petioles 2-8(-18) mm long, 0.2-0.4 mm 
thick, densely stellate-pubescent, apical glands lacking; 
leaf blades 9-35 mm long, 4-18 mm wide, oblong to 
ovate-oblong or elliptic-oblong, apex obtuse or rounded, 
margin minutely serrate with 10-20 small (0.3 m) teeth/ 
side, base obtuse to cuneate, drying chartaceous, sparsely 
stellate-pubescent above with 6-rayed hairs, densely stel- 
late-pubescent beneath with hairs 1-2 mm diam., ve- 
nation subpalmate, 2 veins 3 4/side with basal pair 
prominent. Inflorescences terminal or axillary, 1-4 cm 
long, bisexual or <5, stellate-pubescent throughout, with 
1-3 proximal 9 flowers on slender pedicels 3-8 mm long, 
$ flowers 5-15, solitary in axils of bracteoles 1-2 mm 
long, with glandular margin, pedicels l-2.3(-3.5) mm 
long. Male flower buds ca. 2.2 mm diam., 4-5 mm wide 
at anthesis, sepals 5, 1.2-2 mm long, ca. 1 mm wide, 
acute, sparsely pubescent, petals 1.5-2.5 mm long, ca. 
0.7 mm wide, spathulate-oblong, glabrous except for 
minute white hairs at the blunt apical margin; stamens 
8-12, filaments 1.4-2 mm long, slender, glabrous, an- 
thers 0.5-0.7 mm long. Female flowers 4-6 mm long, 
sepals 5, 4-7 mm long, 0.5-0.7 mm wide, linear-oblong 
with glandular marginal teeth 0.4-1 mm long and few 
stellate hairs; ovary ca. 2 mm long, densely stellate-pu- 
bescent, styles to 4 mm long. Fruits ca. 6 mm long, 
oblong, 3-lobed, stellate-pubescent, columella ca. 3.5 mm 
long; seeds (3-)3.6-4.8 mm long, (2.2-)2.7-3.3 mm wide, 



Croton pachypodus Webster, Ann. Missouri Bot. 
Gard. 75: 1119. 1988. Figure 17. 

Trees 6-30 m tall, bisexual, leafy stems 1.3-4 mm 
thick, with small (0.1-0.4 mm) flat appressed rounded 
peltate hairs; stipules 2-4 mm long, lanceolate to su- 
bulate, caducous. Leaves with petioles 10-45 mm long, 
0.8-1.6 mm thick, densely covered with peltate hairs, 
apex with paired lateral glands 0.4-0.8 mm long, 0.4- 
0.6 mm wide distally, usually cylindrical to stipitate con- 
ic (rarely absent); leaf blades 4-13 cm long, 2-6 cm wide, 
elliptic to elliptic-oblong or ovate-oblong, apex bluntly 
acute to short-acuminate or caudate-acuminate, margin 
obscurely crenate with 5-1 5 small (0.5 mm) sinuses/side, 
base obtuse to slightly rounded, drying thinly to stiffly 
chartaceous, dark and glabrous above or with flat stellate 
hairs, paler beneath with many small (0. 1-0.2 mm diam.) 
flat peltate hairs, venation pinnate, 2 veins 5-8/side. 
Inflorescences terminal (pseudoaxillary), 2-9 cm long, 
racemiform, usually unisexual (bisexual inflorescences 
rare, with 1 9 flower and 2-3 6 flowers in proximal cy- 
mules), with peltate hairs, 9 flowers 1-7, proximal, on 
pedicels 2-7 mm long; <5 flowers in groups of (l-)2-3, on 
pedicels 2.5-5 mm long, covered externally with peltate 
hairs, bracteoles 0.5-1 mm long. Male flowers with 5 
valvate calyx lobes, 1 .2-3 mm long, triangular, petals 2- 
3.2 mm long, ca. 1 mm wide, elliptic to oblanceolate, 
glandular punctate, margins tomentulose, glabrous abax- 
ially; stamens 10-1 3, filaments 2-4.5 mm long, glabrous, 
anthers 0.6-1 mm long. Female flowers 5-7 mm long, 
calyx lobes 5, 2.2-2.7 mm long, triangular or ovate, disc 
ca. 2.8 mm wide, petals apparently absent; ovary 2-3 
mm long, ovoid, densely yellowish with peltate hairs, 
styles 2.5-3.5 mm long, distally bifid, glabrous. Fruits 
3.5-5 cm long, 34 cm wide, obovoid, rounded to trun- 
cated at apex, walls ca. 2 mm thick and woody, surfaces 
covered with peltate hairs, columella 25-34 mm long; 
seeds 20-29 mm long, 1 1-18 mm wide, 8-9 mm thick, 



96 



FIELDIANA: BOTANY 



oblong in outline and slightly convex abaxially, caruncle 
3 mm long, 2.5 mm wide, inverted V-shaped, appressed. 

Trees of evergreen forest formations on both the 
Pacific and Caribbean slopes, 300-1000 m ele- 
vation. Flowering in March-June; with mature fruit 
in July-October. This species ranges from Volcan 
Rincon de La Vieja southward to western Panama. 

Croton pachypodus is recognized by its tall stat- 
ure, small but conspicuous flat peltate hairs, av- 
erage-sized leaves, terminal unisexual racemes, and 
very large capsules and seeds. The ovary is covered 
with lustrous yellowish peltate hairs, and these 
persist but become grayish on the fruits. The flat 
peltate hairs have 20-50 radiating rays united for 
most of their length but separated distally ( x 50). 
This can give the impression of a scurfy or stellate 
form in some instances. Campano is a common 
name. The preceding description is based on Costa 
Rican material and differs from Panamanian ma- 
terial having smaller leaves that are more densely 
pubescent beneath, somewhat larger fruits, and 
fewer stamens/flower. Specimens placed here are 
the following: Bella 1039; Gomez- Laurito 12282; 
Haberetal. 4896, 7036, 7106, 7109, 8395; Ham- 
mel & Grayum 18936; Herrera 607; Holdridge 
6737, 6784; A. Jimenez 1953; Q. Jimenez 635 & 
987; Stork 2811; and Zamora & Poveda 822. Some 
of these collections were earlier misidentified as 
C. tenuicaudatus (q.v.). 



Croton punctatus Jacq., Coll. 1: 166. 1787. Icon. 
PI. Rar. 3: 19, t. 621. 1789. Figure 17. 

Small shrubs 0.3-1 m tall, bisexual, leafy stems 1.4- 
4 mm thick, covered at first with short-stalked flat-topped 
discoid-stellate hairs 0.3-0.5 mm wide, becoming woody 
and black; stipules absent. Leaves with petioles 7-28(- 
37) mm long, 0.6-1.5 mm thick, densely stellate-pubes- 
cent like the stems; leaf blades 1.8-4.5 cm long, 1-2.8 
cm wide, ovate-oblong to oblong, apex bluntly obtuse 
to rounded, margin entire, base rounded and slightly 
truncate, drying stiffly chartaceous or subcoriaceous, pale 
grayish green or yellowish green and paler beneath, upper 
surface with stellate hairs 0.1-0.2 mm wide, lower sur- 
face with rounded stellate-edged hairs 0.3-0.8 mm wide, 
venation pinnate with 4-5 veins/side but usually ob- 
scure. Inflorescences terminal, bisexual, 1-4 cm long, 
peduncles to 14 mm long, ca. 1 mm thick, pubescent, 9 
flowers 1-2 and proximal, subsessile, pedicels to 1 mm 
long in fruit; <5 flowers 4-7. Male flower buds globose, 
ca. 2 mm diam., sepals 5, ca. 2.5 mm long, petals absent; 
stamens 10-12, filaments to 1.5 mm long, anthers 0.8- 
0.9 mm long. Female flowers ca. 4 mm long, 3.5 mm 
wide at apex, sepals 5, 3-3.5 mm long, 1 .8-2.2 mm wide; 
ovary with peltate hairs, styles free, 3 times bifid. Fruits 
ca. 5 mm long, 8-10 mm wide, oblate and 3-lobed, densely 
stellate-peltate, columella 3.8-4.2 mm long; seeds 4.5- 



5.3 mm long, 3.7-4.3 mm wide, 3.2-4 mm thick, ellip- 
soid to subglobose, dark to pale yellowish or mottled. 

Plants of sandy Caribbean seashores, often 
growing within a few meters of the high-tide mark; 
0-20 m elevation. Probably flowering and fruiting 
throughout the year. The species ranges from North 
Carolina (U.S.A.) to Panama and is found on Cuba 
and Bermuda. 

Croton punctatus is distinguished by its restric- 
tion to sandy Caribbean seashores, short dark 
woody stems, small pale grayish oblong leaves with 
entire margins, and rounded apex. The vestiture 
on stems and petioles is unusual. The hairs are 
short-stalked with a flat rounded top that has a 
fringe of minute thin rays (resembling stellate hairs). 
Because of this form the hairs have both a stellate 
and peltate appearance. 

Croton pungens Jacq., Coll. 4: 2 1 7. 1 79 1 . Icon. PI. 
Rar. 3: 19, pi. 622. 1794. Croton standleyi Stey- 
ermark, Publ. Field Mus. Nat. Hist., Bot. Ser. 
22: 151. 1940. Figure 18. 

Shrubs or small trees 1 .2-7(-20?) m tall, bisexual, leafy 
stems 2-5 mm thick, hispidulous with scurfy-stellate hairs 
0.2-0.5 mm diam. or with longer rays 0.6-1 mm long; 
stipules 1-4 mm long, linear or subulate. Leaves with 
petioles 3-13 cm long, 1.3-2 mm thick, stellate-scurfy 
pubescent, with 2-4 stipitate conic, patelliform or dis- 
coid yellowish glands near the apex; leaf blades 5-12(- 
22?) cm long, 3-9(-l 3?) cm wide, ovate to ovate-oblong, 
caudate-acuminate with narrow tip 5-18 mm long, mar- 
gin minutely (0.3 mm) denticulate or subentire, base 
rounded and cordate with sinus 3-18 mm deep, basal 
lobes widely separate to overlapping, drying chartaceous, 
upper surfaces with stellate hairs 0.1-0.4 mm diam., 
lower surface with stellate hairs 0.2-0.8 mm wide, ve- 
nation palmate with 3 major veins, 2 veins 4-8/side of 
the midvein. Inflorescences terminal (pseudoaxillary), 
bisexual, 3-24 cm long, rachis ca. 1.5 mm thick and 
densely stellate, proximal cymules with 9 and 3 flowers, 
distal cymules with 2-5 flowers, bracteoles 1-3 mm long, 
9 flowers subsessile, $ pedicels 3-4(-8) mm long. Male 
flowers stellate-pubescent externally, sepals 5, 2-2.5 mm 
long, 1.1-1.4 mm wide, petals 1.5-2.3 mm long, spathu- 
late, puberulent only along the distal edge, receptacle 
villous; stamens ca. 1 8-40, filaments 2-3 mm long, gla- 
brous, anthers 0.6-0.9 mm long. Female flowers with 5 
sepals 2.2-3.7 mm long, 1.5 mm wide, triangular, petals 
0.3-0.4 mm long, stellate on both surfaces; ovary stellate, 
styles pubescent basally, 4-5 mm long, bifid distally. 
Fruits ca. 7 mm long, scurfy-stellate, columella 5-6 mm 
long; seeds 5.2-6 mm long, 3.7-4.1 mm wide, ca. 3 mm 
thick, rounded but with longitudinal or irregular raised 
areas on adaxial side, caruncle 1.5-1.8 mm wide, round- 
ed. 

Plants of fields, grasslands, and open sites in 
montane forest formations, 1300-2100 m eleva- 



BURGER & HUFT: FLORA COSTARICENSIS 



97 



tion. Flowering collections have been made in Jan- 
uary-February, April, and July-August. In Central 
America, this species is restricted to the Chiriqui 
highlands, Panama, and adjacent Costa Rica; it 
ranges to Brazil. 

Croton pungens is recognized by its smaller cor- 
date leaves, inflorescences with proximal cymules 
having both 9 and <5 flowers, many stamens, larger 
seeds, and restricted occurrence in southern Cen- 
tral America. The hairs of the upper leaf surface 
have minute (0.1-0.2 mm) stalks and flattened 
distal surfaces with ca. 12 radiating points. This 
species is closely related to C. xalapensis (q.v.). 

Croton schiedeanus Schldl., Linnaea 19: 243. 1847. 
C. perobtusus Lundell, Phytologia 1: 405. 1940. 
Figure 17. 

Shrubs or small trees 3-1 5(-25?) m tall, bisexual, trunk 
10-25 cm diam., leafy stems 1.3-6 mm thick, densely 
covered with flat rounded peltate hairs ca. 0.2 mm diam., 
often with a brown center; stipules minute or up to 4 
mm long, ca. 0.5 mm broad at base, linear, deciduous. 
Leaves with petioles 6-50(-58) mm long, 0.7-1.9 mm 
thick, slightly thickened at apex and base, covered with 
peltate hairs, without glands at apex; leaf blades 7-19(- 
29) cm long, 3-8(-l 1) cm wide, elliptic to ovate-elliptic, 
narrowly elliptic-oblong or oblong, apex usually short- 
acuminate with tip ca. 5-7 mm long, margin entire, base 
obtuse to cuneate (rarely rounded and subtruncate), dry- 
ing thinly chartaceous, dark brown to grayish brown, 
sparsely or densely pubescent above (hairs sometimes 
obscure), more densely pubescent beneath with flat pel- 
tate hairs 0.1-0.2 mm diam., venation pinnate, 2 veins 
(7-)9-l 3/side. Florescences terminal or axillary, 1-2/axil, 
racemes (pseudopaniculate when distal leaves fail to de- 
velop), 3-7 (-12) cm long, bisexual or 6, with 1-9 prox- 
imal 9 flowers on long (8-27 mm) pedicels 0.2-0.7 mm 
thick; with many distal 3 flowers solitary in axils of small 
(0.5 mm) bracteoles, <5 pedicals 2-5 mm long, ca. 0.2 
mm thick, pubescence of peltate hairs. Male flower buds 
1.2-1.7 mm diam., 3-6 mm wide at anthesis, white, 
calyx 5-parted, lobes 0.5-1.5 mm long, petals 1-3 mm 
long, with minute white hairs along the edge; stamens 
9-1 1, filaments 1.2-2 mm long, anthers 0.5-1 mm long. 
Female flowers ca. 2-3 mm long, 3-5 mm wide, calyx 
lobes 5, 1.5-3 mm long, 1-1.3 mm wide at base, tri- 
angular, petals 1.5-2 mm long, broadly elliptic, white; 
ovary ca. 2 x 2.3mm, covered with whitish peltate hairs, 
styles branched near the base, 2-3 mm long, usually 3 
times bifid. Fruits 9-13 mm long, 9-12 mm diam., ob- 
long or subglobose, 3-lobed in cross-section, with flat 
hairs 0.2-0.4 mm diam. and conical protuberances ca. 
0.5 mm high, columella 6-9 mm long; seeds 7-9 mm 
long, 4.8-6 mm wide, 2.7-4 mm thick, oblong, caruncle 
0.9-2 mm wide, surface lustrous and yellowish brown 
to mottled dark brown/white. 

Common plants of lowland evergreen and partly 
deciduous forest formations, 0-800(-1200) m el- 
evation (to 1400 m in Chiriqui and adjacent Costa 



Rica). Found within forests, on forest edges, and 
often along streamsides. Flowering in all months, 
but with a majority of collections made in Janu- 
ary-March; fruiting mostly in February-April. The 
species ranges from Mexico to Peru. 

Croton schiedeanus is recognized by its vesture 
of flat appressed-peltate hairs, lack of petiolar 
glands, pinnately veined leaves, long-pedicellate 2 
flowers with many style branches, and many in- 
dividual 6 flowers along the slender racemose floral 
axis. The flat rounded-appressed hairs often have 
a brown or reddish brown center and translucent 
or whitish periphery. Central American collec- 
tions were called C. glabellus L. (C. nitens Sw.) for 
many years, but Webster and Burch (1967, p. 250) 
noted that, though closely related, the Linnaean 
species is restricted to Jamaica and the Cayman 
Islands. (Compare the closely related C. tenuicau- 
datus, and note that small-leaved specimens of C. 
schiedeanus with more rounded blades can look 
very much like C. pachypodus.) This is the most 
commonly collected species of Croton in Central 
America; its name in Costa Rica has been recorded 
as colpachi, colpalchil, copalchi, and quizarra col- 
pachi. 



Croton skutchii Standl., Pub. Field Mus. Nat. Hist., 
Bot. Ser. 22: 86. 1940. 

Trees 10-27(?) m tall, bisexual, leafy stems 4-8 mm 
thick, with flat rounded-peltate hairs 0. 1-0.3 mm diam.; 
stipules minute or absent. Leaves with petioles 7-15 cm 
long, 1 .4-3 mm thick, covered with minute flat or scurfy 
hairs with brown centers, paired lateral/abaxial sessile 
pateliform glands present at the apex, to 2 mm wide, 
thickened tissue ca. 1 mm long also sometimes present 
at the petiole/blade juncture; leaf blades 15-26 cm long, 
10-18 cm wide, ovate-oblong to broadly oblong, or nar- 
rowly ovate-oblong, apex acuminate to obtuse, margin 
entire, base rounded and truncate to subcordate, drying 
chartaceous, drying greenish brown above with scattered 
appressed hairs (in the type) or subglabrous, pale green- 
ish beneath with flat rounded hairs 0.1-0.2 mm diam., 
venation pinnate, 2 veins 1 2-1 7/side. Inflorescences ax- 
illary to distal leaves, 1-2/node, bisexual, 1 5-25 cm long, 
with peltate hairs throughout, with 1-5 proximal solitary 
9 flowers on pedicels 6-1 1 mm long, 1-1.5 mm thick, 
bracteoles subtending the $ glomerules ca. 1 mm long, <5 
flowers in groups of 5-11. Male flowers only seen in 
early anthesis, buds 2-3 mm diam., calyx ca. 4 mm long, 
calyx lobes 1.5-2 mm long triangular, petals ca. 3 x 1 
mm, narrowly obovate; stamens ca. 11, filaments 3-4 
mm long, anthers 1.2x1 mm. Female flowers with sepal 
lobes 4-6 mm long, 3-5 mm wide, oblong, lateral mar- 
gins occasionally reflexed; ovary 2-3 mm high, 3 mm 
diam., covered with lustrous peltate hairs, styles hairy 
at the base, much divided, distal branches more than 
20. Fruits and seeds not seen. 



98 



FIELDIANA: BOTANY 



Plants of evergreen forest formations of the Ca- 
ribbean and Pacific slopes, 600-1000 m elevation. 
Flowering in June and August. The species is known 
only from two collections: Skutch 4377 (us iso- 
type), from near El General, San Jose Province, 
and Lancaster Aug. 5, 1923 (us) from Cachi in 
Cartago Province. 

Croton skutchii is recognized by the flat round 
appressed scales on most surfaces, the larger ob- 
long leaves with many secondary veins and usually 
subcordate base, and the large solitary 9 flowers 
with many style branches. The large broad sepal 
lobes in 9 flowers are distinctive. The flat rounded 
appressed hairs often have a brown center. This 
species superficially resembles C. tenuicaudatus 
(q-v.). 

Croton smithianus Croizat, J. Arnold Arbor. 21: 
93. 1940. Figure 18. 

Trees 5-25 m tall, bisexual, leafy stems 2.5-7 mm 
thick, densely pubescent with sessile or stipitate stellate- 
scurfy hairs 0.3-0.8 mm diam., on stalks to 1.3 mm 
long; stipules 5-9 mm long, 1-2 mm broad at the base, 
lanceolate, caducous. Leaves sometimes opposite at dis- 
tal or flowering nodes, petioles 5-1 5 cm long, 1 .4-3 mm 
thick, densely scurfy-stellate pubescent, with 2 lateral 
sessile saucer-shaped or patelliform glands at the apex, 
0.9-1.3 mm wide; leaf blades ll-26(-35) cm long, 8- 
25(-30) cm wide, broadly ovate and usually distally tri- 
lobed, the broad triangular distal lobes separated by wide 
sinuses 1-5 cm deep, apex obtuse to short-acuminate, 
tip to 6 mm long, margin minutely denticulate with teeth 
0.1-1 mm high (rarely with broadly triangular lobes 5- 
10 mm long), base rounded and cordate to subcordate, 
drying thinly chartaceous, upper surface with stellate hairs 
0.3-1 mm in diam., with 6-12 rays, 0.3-1 mm diam., 
on stalks 0.1-0.5 mm long, more densely pubescent be- 
neath, venation palmate with 3 major veins, 2 veins 3- 
5/side of the midvein. Inflorescences usually unisexual 
(with 5-15 proximal bisexual cymules and distal $ cy- 
mules when bisexual), 20-50 cm long, densely yellowish 
pubescent, 9 flowers solitary with pedicels 5-9(-14) mm 
long, ca. 1.5 mm thick $ fascicles (cymules) with 3-15 
flowers, <5 pedicels 1.5-5 mm long, stellate. Male flower 
buds 3-4 mm diam., calyx 3.5-4 mm long, calyx lobes 
5, 2-3 mm long, triangular, petals 3-4.5 mm long, spath- 
ulate, pubescent; stamens 10-12, filaments 3-4.5 mm 
long, glabrous only distally, anthers 0.8-1.4 mm long. 
Female flowers with 5 valvate sepal lobes, 3-7.5 mm 
long, 2.5-6.5 mm wide, stellate abaxially and on mar- 
gins, disk entire, ovary ca. 1.7 mm wide, styles free, 
hispid, ca. 5 mm long, each style deeply multifid. Fruits 
ca. 8 x 11 mm, yellowish, with scurfy and stellate hairs 
0.1-0.3 mm wide, columella 4-4.5 mm long; seeds 4.7- 
5.1 mm long, 3.7-3.9 mm wide, 2.8-3 mm thick, surface 
with minute longitudinal raised ridges, caruncle 1.7-2.2 
mm wide. 

Plants of evergreen rain forest formations on 
both the Caribbean and Pacific slopes, 20-800 m 



elevation (to 1 500 m in Colombia). Flowering ma- 
terial was collected in June-August; fruiting in 
September. It is rarely collected in Costa Rica (La 
Selva, General Valley, Osa Peninsula). The species 
ranges from southernmost Nicaragua to Colom- 
bia. 

Croton smithianus is distinguished by its large 
leaves with three prominent distal lobes (not pres- 
ent on all leaves), stellate-scurfy pubescence with 
occasional stipitate hairs, cupulate $ calyx, solitary 
9 flowers with broad calyx lobes, many style 
branches, and longitudinally rugulose seeds. Gla- 
brous short-stalked patelliform or saucer-shaped 
glands are sometimes found on the leaf surfaces 
in this species. Specimens lacking the three-lobed 
leaves may be mistaken for C. draco and similar 
species. This species is part of a species complex 
including C. palanostigma Klotzsch, C. benthami- 
anus Mull. Arg., and C. killipianus Croizat (cf. 
Webster & Huft, 1988). 

Croton speciosus Mull. Arg., Linnaea 34: 83. 1 865. 
C. speciosus subsp. tacarcunensis Webster, Ann. 
Missouri Bot. Card. 75: 1119. 1988. 

Shrubs or small trees 3-15 m tall, bisexual, leafy 
branches 2-12 mm thick, densely villose with soft or 
stiff stellate hairs 0.5-2 mm long; stipules 6-12 mm long, 
0.7-2 mm wide at the base, densely villose abaxially, 
entire or with laciniate margins. Leaves with petioles 
1.5_15(_30) cm long, 1.5-2(-4) mm thick, densely stel- 
late-villous, slender stalked glands at apex, usually 2 and 
0.7 mm long or absent in ours (5-10, 5 mm long); leaf 
blades 7-15(-35) cm long, 4-16(-33) cm wide, ovate to 
ovate-triangular or 3-lobed in larger leaves, apex acu- 
minate, margin minutely glandular dentate, rounded at 
the base and subcordate to cordate, whitish beneath with 
a dense tomentum of stellate hairs ca. 1 mm wide, ve- 
nation palmate, 2 veins 4-9/side of the midvein. Inflo- 
rescences terminal or pseudoaxillary, 2-6 cm long, bi- 
sexual, few-flowered, densely pubescent, flowers solitary 
or closely clustered, bracts 5-10 mm long, ca. 1 mm 
wide, <5 pedicels 3-8 mm long, $ pedicels 1-3 mm long. 
Male flowers ca. 8 x 12 mm, calyx lobes 3-5 mm long, 
triangular, petals 4-5 mm long, obovate-spatulate, pu- 
bescent abaxially, glabrous adaxially; stamens 40-70(- 
80), filaments glabrous, anthers ca. 1 .5 mm long. Female 
flowers densely tomentulous, calyx 5-parted, 8-16 mm 
long, valvate, tapering gradually to the acute apex, petals 
absent, disk inconspicuous; ovary 4-6 mm diam., dense- 
ly pubescent, styles 6-9 mm long, 2 times bifid to near 
the base, pubescent except at the tips. Fruits 10-14 mm 
long, subglobose, hispidulous, columella ca. 8 mm long, 
slender; seeds ca. 7 mm long, 5 mm wide, brown, carun- 
cle 2-3 mm wide. 

Rarely collected plants of evergreen forest for- 
mations of the Pacific slope above Buenos Aires, 
at 1500 m elevation. Flowering and fruiting in 



BURGER & HUFT: FLORA COSTARICENSIS 



99 



March (Grayum 10265). The single collection in 
Costa Rica and several collections from Cerro Ta- 
carcuna in eastern Panama are the only records 
for this species outside of Venezuela. 

Croton speciosus is distinguished by the dense 
tomentum on all parts, the large 2 flowers with 
valvate sepals, and the <3 flowers with ca. 50 sta- 
mens. In addition, the larger leaves have three 
distal lobes with narrow acuminate apices, but the 
smaller leaves are unlobed. The Costa Rican col- 
lection is consistent with the description of subsp. 
tacarcunensis in having smaller nonlacerate stip- 
ules, and smaller glands at the apex of the petiole 
than collections from Venezuela. The Costa Rican 
collection has somewhat smaller leaves than typ- 
ical of the species (the larger dimensions of Ven- 
ezuelan material are given in parentheses in the 
preceding description). 

Croton sphaerocarpus H.B.K., Nov. gen. sp., 2: 
84, t. 105. 1817. C. rhamnifolius var. caudatus 
Pax in Pittier, Prim. Fl. Costaric. 2: 331. 1900. 
Figure 16. 

Shrubs l-2(-4) m tall, bisexual, leafy stems 1-3 mm 
thick, at first densely pubescent with stellate hairs 0.2- 
0.9 mm diam., sessile or on short (0.2 mm) stipes, some 
with thin hairs to 0.8 mm long, glabrescent; stipules 2- 
3 mm long, linear. Leaves with petioles 10-25(-42) mm 
long, 0.4-1 .3 mm thick, stellate pubescent, glands absent 
at the apex of the petiole; leaf blades 4-12 cm long, 2- 
6.4 cm wide, ovate to ovate-rhombic or narrowly ovate- 
elliptic, apex acuminate to caudate-acuminate, narrow 
tip 6-30 mm long, margin entire (rarely with teeth ca. 
0.5 mm long), base rounded or obtuse, drying membra- 
naceous or thin chartaceous, dark above with simple or 
stellate hairs, more densely pubescent and grayish be- 
neath with hairs to 0.8 mm diam., mostly with 6-8 rays, 
venation palmate or subpalmate, 2 veins 3-5/side of 
midvein. Inflorescences terminal, 1.5-11 cm long, bi- 
sexual, $ flowers proximal, solitary, 6 flowers in distal 
cymules of 1-3, bracteoles 1.3 mm long, 6 pedicels 1.5- 
3 mm long, filiform, usually glabrous. Male flower buds 
ca. 2 mm diam., sparsely pubescent on the exterior, se- 
pals 5, ca. 1.3 mm long, triangular and acute, petals 
spathulate; stamens ca. 15, anthers 0.6-0.8 mm long. 
Female flowers with sepals ca. 1 mm long, triangular, 
ovary 1.5-3 mm long, 1.3-2.5 mm diam., densely his- 
pidulous with hairs to 0.7 mm long, styles deeply bifid, 
2.5-3 mm long, subglabrous. Fruits ca. 7.5 mm long, 6.8 
mm wide, columella 4.7-5 mm long; seeds 5-5.6 mm 
long, 3.7-4.2 mm wide, 2.2-2.8 mm thick, smooth, car- 
uncle ca. 1.5 mm wide. 

Plants of seasonally very dry deciduous wood- 
lands and open rocky sites, 0-300 m elevation (to 
800 m in Nicaragua). Flowering in May-July; 
fruiting in June-October. It is rarely collected in 
Costa Rica ( Webster & Poveda 22163, Tonduz 2766 



(type of C. rhamnifolius var. caudatus), Wilbur 
21442, Zamora & Chavarria 1028). The species 
is found in Mexico and ranges from northern Nic- 
aragua to northern Guanacaste Province, Costa 
Rica. 

Croton sphaerocarpus is recognized by its thin 
ovate leaves often with long narrow acuminate 
apices, absence of glands at the apex of the usually 
long slender petiole, often slender inflorescences, 
and restriction to seasonally very dry deciduous 
areas. A variety of Nicaraguan collections are 
placed here, ranging from specimens with short 
petioles and stiffly chartaceous ovate-lanceolate 
leaves to specimens with thin broadly ovate leaves 
on long thin petioles. Croton morifolius Willd. of 
Mexico may be an earlier name for this species; 
we follow the annotations of Webster. 

Croton tenuicaudatus Lundell, Phytologia 1:451. 
1940. Figure 19. 

Shrubs or trees to 18 m tall, bisexual, leafy stems 2- 
7 mm thick, covered with peltate rounded hairs 0. 1-0.2 
mm diam. and small (ca. 0.2 mm) straight hairs; stipules 
minute or absent. Leaves with petioles 3-10 cm long, 1- 
2 mm thick, covered with appressed flat hairs, often 
thickened or geniculate at the apex; leaf blades 8-25 cm 
long, 5-12 cm wide, ovate-oblong to broadly oblong, 
acuminate at the apex with a narrow tip 5-15 mm long, 
margin entire, base rounded and broadly obtuse to trun- 
cate, usually drying dark brown above with scattered 
peltate hairs, pubescent beneath with rounded peltate 
hairs 0.1-0.2 mm diam., venation pinnate, 2 veins 8- 
13/side. Inflorescences axillary to distal leaves or ter- 
minal (pseudopaniculate when distal leaves fail to ex- 
pand), 3-16 cm long, <3 or bisexual with 1-5 $ flowers 
proximally, with peltate hairs throughout, 9 flowers sol- 
itary, pedicels 3-7 mm long, ca. 1 mm thick; $ flowers 
solitary, subtended by linear bracts to 2 mm long, ped- 
icels 2-4 mm long. Male flowers ca. 7 mm wide at an- 
thesis, calyx lobes ca. 3 mm long, triangular, petals 5, 
34 mm long, narrowly obovate; stamens 10-13, fila- 
ments to 4 mm long, anthers 1 .2-1 .5 mm long, narrowly 
oblong. Female flowers 6-8 mm wide at anthesis, calyx 
lobes 5, ca. 3 mm long, triangular, petals narrowly ob- 
ovate, 3.54 mm long; ovary ca. 4 mm long, covered 
with lustrous peltate hairs, styles 3 or 4 times bifid, gla- 
brous distally. Fruits not seen (see below). 

Plants of evergreen forest formations from near 
sea level to 900 m elevation, Valle del General, 
to Golfo Dulce. Flowering in November-March. 
This species is known only from the Pacific slope 
of southern Costa Rica and western Panama. 

Croton tenuicaudatus is recognized by the small 
flat rounded peltate hairs on all parts, the larger 
leaves rounded at the base, the lack of glands at 
the apex of the petiole, the solitary flowers, and 
the restricted range. This species is very similar to 



100 



FIELDIANA: BOTANY 



the common and widely ranging C. schiedeanus 
(q.v.), and the two are closely related. It appears 
that ascribing large seeds to this species (Webster 
& Burch, 1 967, p. 253) was an error, with the result 
that this name had been incorrectly used for ma- 
terial now placed in C. pachypodus (q.v.). 

Croton tonduzii Pax in Pittier, Prim. Fl. Costar. 2: 
330. 1990. Figure 17. 

Small trees ca. 6 m tall, leafy stems 1.7-5 mm thick, 
young stems with appressed rounded flat peltate hairs 
ca. 0.2 mm diam.; stipules ca. 1 mm long, caducous. 
Leaves with petioles 3-8 cm long, 1-2.5 mm thick, cov- 
ered with peltate hairs, apex with 2(-4) adaxial sessile 
cupulate or patelliform glands 0.7-1.3 mm diam.; leaf 
blades 9-18 cm long, 3-9 cm wide, broadly ovate (in 
Pittier 3474) to ovate-oblong or oblong (in Pittier 3878), 
apex bluntly acute to obtuse, margin conspicuously den- 
tate-crenate with teeth 0.5-2 mm high, ca. 3 teeth/cm, 
drying thinly chartaceous, dark brown above and gla- 
brescent, paler beneath with many appressed flat round- 
ed hairs ca. 0.2 mm diam., venation palmate (Pittier 
3474) or subpalmate (Pittier 3878), 2 veins 4-8/side. 
Inflorescences terminal, apparently unisexual, becoming 
15 cm long with rachis 2 mm thick, hairs peltate; $ 
flowers not seen; 9 flowers solitary on short (1-2 mm) 
thick (1 mm) pedicels, calyx ca. 2 mm long, lobes 0.7 
mm long; ovary ca. 1.5 mm high and 2 mm diam., 
pubescent. Fruits ca. 7 x 9 mm, oblate, with rounded 
lobes, stellate-peltate, columella 6-7 mm long; seeds 5.5- 
6 mm long, 4.5-4.8 mm wide, 3.5-4 mm thick, pale 
brown, lustrous and minutely rugose. 

Plants of evergreen forest formations on the Pa- 
cific slope between 400 and 800 m elevation. 
Flowering and fruiting in January-February. 
Known from only four collections: Pittier 3474, 
3878 (syntypes), & 12161 and Skutch 4027. En- 
demic to southern Costa Rica (but see below). 

Croton tonduzii is recognized by the peltate hairs, 
leaves with palmate or subpalmate venation and 
denticulate margin, long petioles, and restricted 
habitat. This poorly known species appears to be 
related to C. pachypodus, which has much larger 
fruits and seeds, and to C. mexicanus, where the 
hairs are not so clearly flat and peltate. Croton 
lundellii Standl. of northern Central America may 
be conspecific. This species resembles C. niveus 
and C. schiedeanus and, like them, is called co- 
palchi. 

Croton trinitatis Millsp., Publ. Field Mus. Nat. 
Hist., Bot. Ser. 2: 57. 1900. C. tragioides Blake, 
Contr. U.S. Natl. Herb. 24: 12. 1922. Figure 10. 

Herbs or subshrubs 0.3-0.9(-1.5) m tall, bisexual, of- 
ten with many widely branching stems, leafy stems 0.6- 



4 mm thick, sparsely to densely pubescent with stellate 
hairs 0.3-1 mm long, each hair often with many short 
radiating rays and 1 slightly longer central ray; stipules 
0.4-1.2 mm long, linear. Leaves sometimes subopposite 
at branching nodes, petioles (l-)3-35 mm long, 0.3-0.8 
mm thick, stellate-pubescent, usually with stalked cu- 
pulate glabrous glands 0.4-0.8 mm long at the apex; leaf 
blades 1-6 cm long, 0.6-3.5 cm wide, triangular to ob- 
long or ovate in outline with prominently dentate mar- 
gin, teeth 5-12/side, 1-5 mm long and 2-6 mm wide, 
base of blade rounded to truncate (subcordate), drying 
membranaceous or thinly chartaceous, greenish or gray- 
ish brown, sparsely pubescent above with mostly simple 
hairs to 1 .2 mm long, more densely pubescent beneath 
with stellate hairs ca. 0.3 mm wide, venation subpalmate 
with 3 (5) major veins from near the base. Inflorescences 
terminal or pseudoaxillary, 3-1 5 mm long, few-flowered, 
spicate or branched, stellate-pubescent, with 1-3 prox- 
imal 2 flowers, the 3-8 distal $ flowers borne on slender 
glabrous pedicels ca. 1 mm long, 2 pedicels to 3 mm long 
in fruit. Male flowers globose in bud, ca. 0.7 mm diam., 
ca. 1.5 mm wide at anthesis, sepals 5, ca. 0.8 mm long, 
petals 0.6-0.9 mm long; stamens 8-10, filaments to 1 
mm long, glabrous, anthers 0.3-0.4 mm long. Female 
flowers 3-5 mm long, sepals 5, 3-4 mm long, 0.8-1.7 
mm wide, narrowly oblong to spathulate, petals 0.3-0.4 
mm long, subulate; styles 0.7-1 . 1 mm long, bifid. Fruits 
4-4.5 mm long, 3.5-4 mm diam., oblong, stellate-pu- 
bescent, columella ca. 3 mm long; seeds 3-3.5 mm long, 
2.2-2.5 mm wide, ca. 1.2 mm thick, oblong, with a lus- 
trous usually dark minutely reticulate surface, caruncle 
1.1-1.3 mm wide. 

Plants of open early secondary vegetation in ev- 
ergreen forest formations on both the Caribbean 
and Pacific slopes, 0-1 100 m elevation. Flowering 
in April-September; fruiting in April-February. 
This species ranges from eastern Mexico to Peru. 

Croton trinitatis is recognized by its short her- 
baceous habit, distinctive narrowly triangular 
leaves with prominent teeth, short few-flowered 
inflorescences, and the stipitate glands at the apex 
of the petiole. 

Croton xalapensis H.B.K., Nov. gen. sp. 2: 85. 
1817. C. pseudoxalapensis Croizat, J. Arnold 
Arbor. 21: 85. 1940. C. pseudoxalapensis var. 
cobanensis Croizat, J. Arnold Arbor. 21: 86. 
1940. Figure 18. 

Shrubs or small trees 2-1 5 m tall, bisexual, leafy stems 
2-7 mm thick, densely white or yellowish hispidulous 
with scurfy-stellate hairs 0.3-0.5 mm diam. and often 
with thin simple hairs to 1.5 mm long; stipules 2-5 mm 
long, linear, caducous. Leaves with petioles 1.5-14 cm 
long, 1-3 mm thick, densely stellate-hispidulous, with 2 
(3-7) usually stipitate and conical or sessile saucer-shaped 
glands 0.6-2.3 mm long, 0.6-0.9 mm diam. at apex; leaf 
blades 5-24(-32) cm long, 2-14(-20) cm wide, ovate to 
narrowly ovate-oblong, apex long-acuminate to caudate- 
acuminate, margin minutely (0.3-1.5) denticulate or 
subentire, base rounded and truncate or shallowly cor- 



BURGER & HUFT: FLORA COSTARICENSIS 



101 



date (obtuse), drying thinly chartaceous, with scattered 
small (0.2-0.4 mm) stellate hairs above, more densely 
pubescent beneath with somewhat larger hairs, venation 
subpalmate or pinnate, basal secondaries usually prom- 
inent, 2 veins 5-10/side. Inflorescences 5-25(-40) cm 
long, unisexual or bisexual, spicate, densely stellate pu- 
bescent, 9 flowers solitary, not associated with <5 flowers, 
subsessile; 6 flowers solitary or in glomerules of 2-7, 
pedicels to 8 mm long, bracteoles to 4 mm long. Male 
flowers ca. 6 mm wide at anthesis, calyx 2.5-3.5 mm 
long, sepals 5, 1.5-2.3 mm long, 1.5-2 mm wide, tri- 
angular, petals ca. 3 x l .2 mm; stamens 1 8-3 1 (in Costa 
Rica), filaments 1.8-4 mm long, glabrous distally, an- 
thers 0.5-1 mm long. Female flowers with sepals 1.5-4 
mm long, ca. 1.3 mm wide at base, up to 7 x 3 mm in 
fruit; ovary 2-3 mm long, 3-4 mm diam., densely stel- 
late-hispidulous, styles 2.3-3.5 mm long, bifid from near 
the base. Fruits 6-7 mm long, ca. 7-9 mm wide, stellate- 
pubescent, columella 5-6 mm long, ca. 2 mm wide at 
apex; seeds 4.8-5.7 mm long, 3.74.4 mm wide, ca. 3.7 
mm thick, with raised transverse-angular areas on both 
adaxial and abaxial surfaces, caruncle ca. 2 mm wide. 

Plants of montane evergreen and partly decid- 
uous forest formations, 700-2100 m elevation. 
Probably flowering and fruiting throughout the year 
but collected most often in February-September. 
The species ranges from Veracruz, Mexico, to the 
central highlands of Costa Rica (and to 8303'W 
on the Caribbean slope of the Talamanca moun- 
tains). 

Croton xalapensis is recognized by its often larg- 
er ovate-oblong leaves truncate or subcordate at 
the base, stipitate glands near the apex of the pet- 
iole (not always present), dense pubescence of stel- 
late hairs, $ flowers with 14-33 stamens, and seeds 
with transverse-oblique raised areas. Leaf vena- 
tion is generally pinnate, unlike most of our other 
large-leaved Croton species. The larger hairs are 
distinctive in being slightly (0. 1-0.2 mm) stipitate 
and having 8-24(-many) short rays, often giving 
a somewhat scurfy appearance. This species has 
been called targud, targud bianco, and terre in Cos- 
ta Rica. This species is closely related to C. pun- 
gens of the Chiriqui Highlands. Compare also C. 
draco and C. hoffmannii, 

Croton yucatanensis Lundell, Phytologia 1: 408. 
1940. Figure 16. 

Shrubs 2-3 m tall (rarely to 7 m), bisexual, leafy stems 
1^4 mm thick, densely whitish stellate-tomentulose in 
early stages, hairs stellate or stellate-peltate with a small 
(0.1-0.2 mm) flat central area; stipules often broader 
than long and leaf-like (sometimes absent or minute and 
linear), 3-8 mm long, to 14 mm wide and reniform, 
caducous or persisting. Leaves with petioles 5-32 mm 
long, 0.6-2 mm thick, whitish with stellate hairs, small 
(0.3 mm) sessile glands or stipels usually present at the 



adaxial apex; leaf blades 2-1 1(-13) cm long, 1.5-5(-7) 
cm wide, ovate-oblong, ovate-lanceolate, lanceolate or 
ovate-oblong, apex bluntly obtuse to acuminate, margin 
entire to subentire, base obtuse to rounded and subcor- 
date, drying chartaceous and dark above, whitish be- 
neath with a dense tomentum of stellate hairs 0.1-0.3 
mm wide, venation palmate or subpalmate, 2 veins 2- 
6/side of the midvein. Inflorescences terminal, 1-2, 3- 
1 5 cm long, bisexual or unisexual, with whitish stellate 
hairs throughout, flowers solitary, $ bracts ca. 0.7 mm 
long, pedicels 3-4 mm long; $ bracts 1-2 mm long, 2 
pedicels to 6 mm long in fruit. Male flowers ca. 4 mm 
wide, calyx lobes 5, 1.7-2 mm long, acute, petals nar- 
rowly oblong; stamens ca. 1 5, 3-4 mm long, anthers 0.7- 
1 mm long. Female flowers 3-6 mm long, calyx lobes 5, 
2-5 mm long, 3 mm wide at base, broad and often with 
lateral margins reflexed, disk adnate to base of perianth, 
ovary ca. 2.7 mm long, styles 2-4 mm long, bifid at the 
base and also bifid distally (ca. 1 2 style branches/flower), 
densely pubescent in lower part. Fruits 5-6 mm long, 6- 
7 mm wide, oblate, sparsely stellate-puberulent, colu- 
mella ca. 3 mm long; seeds 3.84 mm long, 3-3.2 mm 
wide, 2.2-2.4 mm thick, slightly rugose with minute lon- 
gitudinal ridges on abaxial surface, caruncle 0.7-0.8 mm 
wide. 

Plants of deciduous forest formations of north- 
western Guanacaste Province (Santa Rosa N.P. 
and vicinity), 0-300 m elevation (400-600 m in 
Nicaragua). Flowering in May-June; probably 
fruiting in July-August. This species ranges from 
southern Mexico to northwestern Costa Rica. 

Croton yucatanensis is easily identified by its 
broadly rounded leaf-like stipules, but these may 
not be present in all collections and are often ca- 
ducous. The white stellate pubescence of some- 
what flattened/peltate hairs, short stature, and 
broad often reflexed 2 calyx lobes are additional 
distinctions. The ca. 24-32 peripheral rays of the 
hair are united laterally only near the center ( x 50). 
Our collections were earlier identified as C. wat- 
sonii Standl., a similar species of Mexico. See the 
discussion under the following species. 

Croton sp. aff. C. yucatanensis Lundell, Phytologia 
1: 408. 1940. Figure 16. 

Small trees 3-10 m tall, bisexual, leafy branchlets 1.3- 
3.7 mm thick, densely stellate-tomentulose with whitish 
hairs; stipules absent or minute (sometimes 1.5-4 mm 
long near the inflorescences). Leaves with petioles 1 1- 
45 mm long, 0.8-1.4 mm thick, whitish stellate-tomen- 
tulose, glands absent or with minute glands on adjacent 
lamina margin; leaf blades 2.5-12 cm long, 1.8-5.5 cm 
wide, ovate to ovate-oblong or ovate-elliptic, apex acute 
to acuminate, margin subentire, base obtuse to rounded 
and subcordate, drying chartaceous and dark above with 
scattered minute (0. 1-0.2 mm) stellate hairs, bright whit- 
ish beneath with appressed stellate hairs, venation pal- 
mate or subpalmate, 2 veins 3-6/side of 1 vein. Inflo- 
rescences 5-17 cm long, terminal or axillary to distal 



102 



FIELDIANA: BOTANY 



leaves, usually solitary, bisexual with many proximal 9 
flowers and distal <3 flowers, solitary or crowded, rachis 
1-2 mm thick, densely whitish stellate-tomentulose, 6 
pedicels 3-6 mm long, ca. 0.5 mm thick, 9 pedicels 2-6 
mm long, ca. 1 mm thick. Male flowers ca. 6 mm wide, 
sepal lobes 5, 2.5-3 mm long, 2-2.5 mm wide, triangular, 
obtuse, petals 3.5-4 mm long, ca. 1.5 mm wide, oblong; 
stamens 11-14, filaments 3-4 mm long, anthers 1-1.4 
mm long. Female flowers 5-8 mm long, calyx lobes 3- 
6 mm long, 1.8-4 mm wide, oblong-obovate, apex 
rounded or obtuse, lateral margins sometimes reflexed; 
ovary 3-4 mm long, densely tomentulose, styles densely 
puberulent, with 1 5-40 distal style branches/flower. Fruits 
ca. 6 mm long, 3.4-3.6 mm wide, 2.6-3 mm thick, sur- 
face smooth, caruncle 1.5-2 mm wide. 

Small trees of deciduous and partly deciduous 
forest on the seasonally dry Pacific slope of the 
Cordillera de Tilaran, 700-1100 m elevation. 
Flowering in June-July; fruiting in July. Collec- 
tions placed here are Bella 2912 and Haber et al. 
1777, 9944, 9986, 10734, & 10735. These were 
collected in the upper Rio Lagarto and Rio Luis 
drainages below Monteverde, near the border of 
Guanacaste and Puntarenas provinces. 

Croton sp. aff. C. yucatanensis is recognized by 
its restricted habitat, bright white stellate hairs 
covering the lower leaf surfaces and inflorescences, 
the broadly reflexed 9 sepal lobes, and the many 
style branches. While very similar in overall ap- 
pearance to C. yucatanensis, the material placed 
here differs in lacking the expanded stipules, hav- 
ing fewer stamens, more divided style branches, 
and larger seeds. The tree habit and higher ele- 
vation habitat also separate the two. This material 
keys to section Lasiogyne (Klotzsch) Bullion in 
Webster's recent review (Webster, 1993) and is 
also related to C. tabascensis Lundell, which rang- 
es from Mexico to Nicaragua. Croton tabascensis 
differs from our material in having 15-16 stamens 
per flower, slender subglabrous style branches only 
twice bifid, and leaves with the pubescence less 
dense beneath. It is possible that all these taxa are 
actually part of a single polymorphic complex. 

Croton sp. A. 

Small tree ca. 9 m tall, bisexual, leafy stems 1-4 mm 
thick, stellate-pubescent with flat hairs 0.3-0.4 mm diam.; 
stipules ca. 3 mm long, linear, caducous. Leaves subop- 
posite at some nodes, petioles 3-9.5 cm long, 1-2 mm 
thick, stellate-pubescent, apex with paired lateral sub- 
sessile cupulate glands 0.3-0.6 mm diam.; leaf blades 9- 
20 cm long, 3-9 cm wide, ovate-elliptic to lanceolate or 
oblong, apex long-acuminate with narrowed tip to 20 
mm long, margin subentire or with few teeth to 3 mm 
high, base obtuse, drying membranaceous and dark above 
with scattered stellate hairs, stellate hairs on lower sur- 
face 0.5-1 mm diam. and evenly spaced, hairs flat with 



usually 7 slender rays, small (0.2 mm diam.) stalked 
glands present near vein axils, venation pinnate (sub- 
palmate), 2 veins 4-7/side, loop-connected in the distal 
part of the lamina. Inflorescences terminal or pseudoax- 
illary, ca. 15 cm long, apparently bisexual, rachis 0.7-1 
mm thick, stellate-pubescent, $ flowers in small glom- 
erules of 1-4, bracts inconspicuous (ca. 0.5 mm); 9 flow- 
ers not seen. Male flower buds ca. 2 mm diam., sepals 
valvate, petals ca. 3 mm long, oblong-obovate; stamens 
16, filaments glabrous, anthers 0.8-1 mm long, 0.6-0.9 
mm wide. Fruits not seen, persisting pedicel 5 mm long, 
1.5 mm thick, columella 1 1 mm long, 1.5 mm wide at 
apex. 



Croton sp. A is distinguished by its unusual 
leaves, which are thin-textured, borne on long pet- 
ioles, and have pinnate venation and long-acu- 
minate apices. In addition, lower leaf surfaces have 
flat stellate hairs with fewer than 1 rays and small 
stalked glands near the axils of both 2 and 3 veins. 
The leaves are aromatic when crushed. This un- 
usual species is known only from a single collec- 
tion: Gonzalez, Poveda, & Barquero 196 (MO), made 
on 10 October 1992 near the Rio Corinto 
(1011'55"N, 8353'20"W) at 250 m in a Carib- 
bean rain forest (premontane wet forest) forma- 
tion. This species is being studied by its discoverer, 
Jose Gonzalez, who has found three trees in the 
only known population. 



Dalechampia Linnaeus 

REFERENCES G. L. Webster & W. S. Armbrus- 
ter, A synopsis of Neotropical Dalechampia (Eu- 
phorbiaceae). Dot. J. Linn. Soc. 105: 137-177. 
1991. W. S. Armbruster, A new species, section 
and synopsis of Dalechampia (Euphorbiaceae) from 
Costa Rica. Syst. Bot. 13: 303-312. 1988. 



Vines or lianas, rarely subshrubs or small erect few- 
branched shrubs, monoecious, pubescence of simple uni- 
cellular hairs, specialized stinging hairs present in some 
species; stipules free, lateral, acute, often with parallel 
venation, persisting or caducous. Leaves alternate, sim- 
ple or palmately compound, often variable on the same 
plant with distal leaves more lobed or divided, usually 
petiolate, often with a pair of stipel-like glands at the 
base of the blade, blades entire to dentate or deeply 
lobed, venation palmate or pinnate. Inflorescences ax- 
illary or terminal, usually solitary, bisexual, often borne 
on axillary stems with reduced leaves, flower-like pseu- 
danthia with 2 large subopposite usually colorful invo- 
lucral bracts, palmately veined, margin entire to dentate 
or laciniate, the 2 involucral bracts subtended by 4 small 
involucral stipules. Male cymules with various arrange- 
ments (mostly a pleiochasium of several 1-3-flowered 
cymules), usually with a pedunculate 2-lipped involucel 



BURGER & HUFT: FLORA COSTARICENSIS 



103 



with a row of stamens facing the 9 cymule and a sticky 
resiniferous gland facing the upper involucral bract (in- 
volucel of 2 alternate decussate bracts in some species). 
Male flowers mostly 8-12, with articulated pedicels, ca- 
lyx globose in bud and splitting into 3-6 valvate parts, 
becoming reflexed, disk and petals absent; stamens most- 
ly 20-50 (8-1 00+), filaments connate in a stiff column, 
filaments very short, anthers bilocular, dehiscing longi- 
tudinally; pistillode absent. Female cymules inserted 
above the lower involucral bract and below the <5 flowers, 
2 cymes usually with 3 flowers (1 in D.ficifolld), $ flowers 
subtended by an involucel of 1 lower (proximal) bract 
and 2 distal bracteoles or a single 2-lipped involucel 
formed by fused bracteoles. Female flowers subsessile or 
pedicellate, sepals 5-12, imbricate, mostly pinnatifid with 
gland-tipped lobes in Neotropical species, expanding in 
fruit, petals, staminodes and disk absent; ovary 3- 
(4-)locular, ovules 1/locule, styles united to form a col- 
umn, often expanded into a peltate stigma (style branch- 
es absent). Fruits capsules, splitting explosively into 3 
(4) 2-valved cocci, endocarp crustaceous or woody, often 
developing stiff sharp hairs on the surface, columella 
persisting; seeds subglobose to ellipsoid, sui faces smooth 
to tuberculate, ecarunculate, endosperm present, coty- 
ledons broad. 



A genus of 95 Neotropical and ca. 20 Old World 
species. The inflorescence is very unusual and 
functions like a large individual bisexual flower, 
usually held vertically with the 9 flowers below the 
6. The large pulviniform nectary is interpreted to 
be a modification of bracteoles of undeveloped <5 
cymules. (For a recent study of these unique in- 
florescences, see H. Froebe & N. Magii, Pattern 
analysis in the inflorescences of Dalechampia L., 
Bot. Jahrb. Syst. 115: 27^4, 1993.) Inflorescences 
of the same species can differ greatly in appearance 
during different stages of flowering and fruiting, 
and this can make identification quite difficult. 
Neotropical species are largely pollinated by 2 bees 
gathering resin from the large gland or by <5 euglos- 
sine bees gathering aromas. Most species are not 
well represented in herbaria, but it is difficult to 
determine whether this is due to the difficulty of 
discerning vining plants, the rarity of the species, 
or the stinging pubescence in some species. 



Key to the Species of Dalechampia 

la. Plants erect shrubs 0.5-1.5 m tall, central stem usually without lateral branches; leaves simple 
with pinnate venation, oblanceolate or narrowly elliptic-obovate, to 28 cm long; gland of <? involucel 

yellow and lacking resin; seeds minutely tuberculate D. spathulata 

Ib. Plants climbing or clambering vines and lianas, lateral branches frequent; leaves simple with 
palmate venation and never oblanceolate, or compound and 3-foliolate; gland of <5 involucel absent 

or producing clear, white, or maroon resin; seeds smooth or minutely rugulose 2 

2a. Compound leaves with independent leaflets present, simple or lobed leaves sometimes also present 

3 

2b. Compound leaves absent, leaves sometimes deeply 3-lobed but the lobes not narrowed into basal 

petiolules 5 

3a. Trifoliolate leaves and simple ovate leaves often intermixed on stems; hairs of stems often 
clearly retrorse [9 sepals 7-11; seeds 3.5-4.2 mm diam., involucral stipules 2-3 mm long] 

D. heteromorpha 

3b. Trifoliolate and simple ovate leaves rarely intermixed along the stems; larger stem hairs erect 

and the smaller often retrorse 4 

4a. Female sepals 7-11; seeds 2.84.2 mm diam.; involucral stipules 2-5 mm long, involucral 

bracts greenish at anthesis; 400-1 100 m elevation D. cissifolia 

4b. Female sepals 6; seeds 45 mm diam., involucral stipules 10-14 mm long; involucral bracts 

greenish or white at anthesis; 0-400 m elevation D. websteri 

5a. Stems, leaves, and bracts hirsute or lanate with orange or yellow-orange hairs to 2 mm long; larger 
leaves usually more than 15 cm long, 3-lobed and unlobed leaves often present on same plant; $ 
involucel with 4 free bracteoles, glandular-laciniate [evergreen lowlands to 200 m elevation] . . 6 
5b. Stems, leaves, and bracts not densely hirsute with yellow-orange hairs, hairs rarely exceeding 1 
mm; larger leaves rarely > 15 cm long, 3-lobed and unlobed leaves not usually present on the 
same plant (except D. tiliifolia); $ involucel with free or united bracteoles but not glandular-laciniate 

7 

6a. Male flowers usually 13; stigmas ca. 2 mm wide, distinct resin gland absent; margin of leaf 

blades minutely denticulate; Caribbean lowlands D. shankii 

6b. Male flowers usually 10; stigmas 24 mm wide, distinct gland with white resin present; 
margins of leaf blades entire or obscurely denticulate; Osa Peninsula D. osana 



104 



FIELDIANA: BOTANY 



7a. Leaves ovate, consistently without lobes, deeply cordate at the base; involucral bracts deciduous 

before fruits become mature; 6 involucel of 4 free bracteoles 8 

7b. Leaves usually deeply 3-lobed, occasionally ovate; involucral bracts often persisting as fruits de- 
velop; 6 involucel with bracteoles united near base or throughout 10 

8a. Fruiting sepals ca. 4 mm wide, unlobed and with laciniate margins; seeds 4-4.5 mm diam.; 
stipules 6-12 mm long; stems and leaves sparsely hirsute with hairs 1-2 mm long [rare in 

Costa Rica] D. canescens 

8b. Fruiting sepals narrow (ca. 1 mm) with slender lateral pinnatifid lobes 1-8 mm long; stipules 

2-7 mm long; stems and leaves lacking longer (1-2 mm) hairs 9 

9a. Pinnatifid lobes of the fruiting sepals 4-12 mm long; seeds 4.8-5.8 mm long and with 3 

longitudinal ribs; leaves usually broadly ovate D. dioscoreifolia 

9b. Pinnatifid lobes of fruiting sepals 1-2 mm long; seeds 2.84.2 mm long, subglobose with 

smooth surface; leaves usually narrowly ovate D. cissifolia 

lOa. Leaves usually deeply 3-lobed, never 3-foliolate; from both deciduous and evergreen formations 

on the Pacific slope (in Costa Rica) 11 

lOb. Leaves usually ovate and unlobed (sometimes 3-foliolate in D. heteromorphd); from evergreen or 

partly deciduous formations on both Pacific and Caribbean slopes 12 

1 la. Involucral bracts with 3 short distal lobes (< % length of bract); $ bracteoles free for ca. '/2 

their length; seeds 4-5 mm diam.; evergreen or partly deciduous areas, 0-500 m 

D. tiliifolia 

1 Ib. Involucral bracts with 3 lobes l A- l /2 the length of the bract; $ bracteoles united into a cup- 
like or bilabiate structure; seeds 3.64.2 mm diam.; deciduous or evergreen areas, 0-1000 

m D. scandens 

12a. Leaf base with a usually shallow (0-1 cm) sinus, leaves narrowly ovate-triangular and unlobed or 
sometimes 2-lobed; involucral bracts with 5 main veins from base, deeply 3-lobed to unlobed, 
green as the leaves; evergreen or partly deciduous formations of the Pacific slope, 0-1100 m 

elevation D. heteromorpha 

12b. Leaf base with a conspicuous basal sinus 1-2 cm deep, leaves ovate and unlobed; involucral bracts 

with 7-9 main veins, distally 5-lobed, pale green; evergreen Caribbean slopes ca. 500 m 

. D. arenalensis 



Dalechampia arenalensis Armbruster, Syst. Bot. 
9: 275. 1984. 

Clambering vines, stems 0.5-1 mm thick distally, pu- 
bescence of strigose hairs 0.5-0.8 mm long; stipules 8- 
10 mm long, 2-4 mm wide, lanceolate, weakly parallel- 
veined, persisting. Leaves simple, petioles 1-6 cm long, 
0.8-1.2 mm thick, pubescent as the stem, stipels 2 at 
base of blade, 1-2 mm long, 0.8-1.2 mm wide, gland- 
tipped and with 1-2 marginal glands; leaf blades 6-14 
cm long, 3-8 cm wide, ovate to broadly ovate, apex 
acuminate, margin entire to glandular-sinuate, base cor- 
date, sinus 1-2 cm deep, drying chartaceous, surfaces 
strigulose, venation palmate with 3-5 major veins. In- 
florescences borne on axillary shoots 5-25 cm long, pe- 
duncles 3-4 cm long at anthesis (to 6 cm in fruit), in- 
volucral stipules 3-8 mm long, 1.5-2 mm wide; invo- 
lucral bracts subequal, 3-4.5 cm long, 2.5-3.5 cm wide, 
broadly ovate, 5-lobed distally, middle lobe 1.8-2.5 cm 
long, rounded-subcordate at base, palmately 7-9-veined, 
margins glandular dentate, pale green; resin gland 26- 
38 mm long. Male cy mules with peduncles 3-5 mm long, 
1.5-2.5 mm thick, involucel shallowly 2-lipped, lower 
lip (subtending $ flowers) ca. 5 mm long, 8-10 mm wide, 
margin deeply undulate, upper lip subentire; 3 flowers 
10(1 terminal with 3 lateral 3-flowered groups), with ca. 
20 small (2-3 mm) resiniferous bracteoles; <3 pedicels 5- 



7 mm long, calyx splitting into 5-6 ovate parts, 2-3 mm 
long, ca. 2 mm wide, reflexed, staminal column 3-4 mm 
long, 0.7-1.5 mm thick, anthers (13-) 18-30, filaments 
ca. 0.5 mm long, anthers ca. 1.5 mm long. Female cy- 
mules sessile, involucel of 2 bracteoles, 4-8 mm long, 
adaxial bracteole 12-15 mm wide, abaxial 47 mm wide; 
2 flowers subsessile at anthesis, sepals usually 1 2 on cen- 
tral flower and 9-10 on lateral flowers, 1-1.5 mm wide, 
with laciniate eglandular teeth, ovary ca. 1.5 mm diam., 
stylar column 13-16 mm long, curving upward, ca. 1.2 
mm thick, tip slightly discoid. Fruits 10-12 mm diam., 
borne on pedicels 10-20 mm long, fruiting sepals 15-20 
mm long, linear, with gland-tipped teeth along margin, 
sharp hairs 1-2 mm long; seeds ca. 4 mm diam., globose, 
minutely rugulose, mottled brown. 



Plants of evergreen Caribbean rain forest for- 
mations, 300-500 m elevation. Flowering in Jan- 
uary and August. Known only from the following 
collections Armbruster & Herzig 79-215 DAV (type) 
and Lent 2766 MO, both from the northern slopes 
of Volcan Arenal in north-central Costa Rica. 

Dalechampia arenalensis is recognized by its 
simple ovate leaves with narrow basal sinus, in- 



BURGER & HUFT: FLORA COSTARICENSIS 



105 



volucral bracts green at anthesis, yellow floral res- 
in, and restricted range. 

Dalechampia canescens H.B.K., Nov. gen. sp. 2: 
98. 1817. D. friedrichsthalii Mull. Arg., Flora 
55: 45. 1872. D. canescens ssp. friedrichsthalii 
(Mull. Arg.) Webster & Huft, Ann. Missouri Hot. 
Gard. 75: 1109. 1988. 

Climbing vines, leafy stems ca. 2 mm thick, minutely 
puberulent and with few straight longer hairs to 1.5 mm 
long; stipules 6-12 mm long, 2-3 mm wide at base, 
lanceolate, pubescent, venation parallel, reflexed and 
persisting. Leaves simple, petioles 5.5-9.5 cm long, pu- 
bescent as the stems, stipels 1.8-3 mm long, lanceolate, 
glandular at the base; leaf blades 7-14 cm long, 5-10 cm 
wide, ovate to triangular-ovate, apex abruptly short-acu- 
minate, margin subentire or minutely denticulate, base 
deeply cordate with lobes often overlapping, drying char- 
taceous, sparsely hirsute above, minutely puberulent be- 
neath, venation palmate with 3 major ascending veins. 
Inflorescences axillary to leaves, solitary, peduncles (in- 
cluding axillary stem with caducous leaf) 7-10 cm long, 
involucral stipules 12-13 mm long, 3.5-5 mm wide, 
pubescent and hispid-ciliate, parallel-veined; involucral 
bracts white with green veins, ca. 3 cm long, ovate, with 
3 short distal lobes, middle lobe ca. 8-9 mm long, acu- 
minate, margins lacerate, 5-veined at base with petiole 
1.5-2 mm long. Male cy mules with thick peduncle 1.5- 
2 mm long, involucel of 4 bracts, 4-5 mm long, 7-8 mm 
wide, broadly imbricate; <5 flowers ca. 10, pedicels 2-3 
mm long, articulate near apex, buds 1.5-2.5 mm diam., 
sepals 4-5, stamina! column 1.3-2 mm long, hispidu- 
lous, anthers (18-)2 5-3 3. Female cymules with 2 adaxial 
bracteoles 5-5.5 mm long, abaxial bracteole ca. 4.5 x 6 
mm, broadly ovate or reniform, crenate-toothed; 2 flow- 
ers with 5-8 sepals, 1.7-2.2 mm long at anthesis, ovate- 
oblong, margin fimbriate; ovary deeply 3-lobed, mi- 
nutely hispidulous, styles 9-10 mm long, stigma 1-1.5 
mm wide. Fruits ca. 7 mm long, ca. 9 mm wide, sub- 
tended by the persisting involucral stipules and narrow 
sepals to 12-15 mm long and 4 mm wide, margins la- 
ciniate; seeds 4-4.5 mm diam., subglobose, slightly ru- 
gose-costate. 



Rarely collected plants of evergreen lowland for- 
est formations. The species ranges from the Rio 
San Juan, Nicaragua (Friedrichsthal 683, o type 
of D. friedrichsthalii, not from Guatemala as ear- 
lier described) to Peru. 

Dalechampia canescens is recognized by the 
simple ovate-triangular leaves with conspicuous 
narrow basal sinus, the broader parallel- veined in- 
volucral stipules, the lanceolate laciniate sepals 
subtending the fruits, and the slightly rugose seeds 
with weakly developed longitudinal costa. The 
above description is based on earlier descriptions: 
we have seen no material from Costa Rica. 



Dalechampia cissifolia Poeppig in Poeppig & Endl., 
Nov. gen. sp. pi. 3: 20. 1845. D. trifolia Lam., 
var. cissijlora (Poeppig) Mull. Arg. in DC, Prodr. 
15 (2): 1239. 1866. D. panamensis Pax & K. 
Hoffm., Pflanzenreich IV, 147, XII: 19. 1919. 
D. cissifolia ssp. panamensis (Pax & K. Hoffm.) 
Webster, Ann. Missouri Bot. Gard. 54: 193. 
1967. Figure 4. 

Climbing vines, leafy stems 0.7-3.5 mm thick, pu- 
bescent with thin whitish retrorse hairs 0. 1-0.5 mm long, 
with few to many longer erect hairs to 2 mm; stipules 
2-6 mm long, 0.3-0.7 mm wide at base, lanceolate to 
linear, reflexed. Leaves 3-foliolate (rarely 5-foliolate or 
simple), petioles 1.5-8 cm long, 0.5-1.3 mm thick, pu- 
bescent, stipels 2, 1-3.5 mm long, 0.4 mm wide, glan- 
dular at base, petiolules of central leaflet 1-6 mm long; 
leaflet blades (middle leaflets) 4-1 1 cm long, 1.1-3.5 cm 
wide, narrowly elliptic-oblong to narrowly ovate-elliptic, 
apex acute to acuminate, margins subentire or with 2-5 
short (0.5 mm) teeth/cm, base acute, lateral leaflets 
asymmetric at base with a rounded-truncate side and 
cuneate side, drying thinly chartaceous, sparsely and mi- 
nutely (0.1-0.2 mm) puberulent on the veins beneath, 
larger (0.4-0.7 mm) hairs sometime present on the sur- 
faces, venation pinnate, 2 veins 5-7/side, 3 veins sub- 
parallel. Inflorescences axillary (short shoots to 5 mm 
long), peduncles 6-18 mm long (to 25 mm in fruit), 0.3- 
0.6 mm thick, pubescent, involucral stipules 2-5 mm 
long, 0.7-1 .7 mm wide at base, subulate, involucral bracts 
8-18 mm long, 9-23 mm wide, to 25 x 29 mm in fruit, 
broadly ovate and 3-lobed or unlobed, middle lobe 3-8 
mm long, margin with short (0.5 mm) teeth, greenish. 
Male cymules subsessile, involucel 1.5-2 mm long, 5-8 
mm wide, reniform, pedicels 2-3 mm long; $ flowers 8- 
9, buds 1.5-2 mm diam., calyx lobes 4-5, staminal col- 
umn ca. 1 mm long, anthers 20-36. Female cymule with 
3 flowers, sepals 7-11, unequal and slender-pinnatifid 
with 4-6 slender lobes/side; ovary densely hispid, stylar 
column 5-6 mm long, stigma 0.6-1 mm wide. Fruits 5- 
6 mm long, 8-10 mm wide, with 3 rounded lobes, mi- 
nutely puberulent, subtended by sharp-hispid pinnatifid 
sepals 7-1 1 mm long, 0.6-2 mm wide, lobes 0.5-2 mm 
long, stinging hairs to 1 mm long, columella 2.8-4.2 mm 
long, 3.7-4.2 wide at apex; seeds 2.8-4.2 mm long, glo- 
bose, dark to pale brown, smooth, usually mottled. 



Plants of evergreen forest formations of the Pa- 
cific slope, 400-1 100 m elevation (0-1 500 in Gua- 
temala). Fruiting in November-March. Collected 
only on the Cordilleras de Guanacaste and Tilaran 
and near San Ramon in Costa Rica (but see below). 
The species ranges from Mexico to Peru. 

Dalechampia cissifolia is recognized by its pal- 
mately three-foliolate leaves (rarely simple and 
ovate), greenish involucral bracts often with three 
distal lobes, and the "involucre" of 7-1 1 stiff nar- 
row sepals with short narrow lateral lobes and 
stinging hairs subtending the fruits. It is possible 



106 



FIELDIANA: BOTANY 



that D. heteromorpha will be reinterpreted as an 
unusual form of this species. 

Dalechampia dioscoreifolia Poeppig in Poeppig & 
Endl., Nov. gen. sp. pi. 3: 20. 1841. Figure 5. 

Climbing vines, leafy stems 1 .2-4 mm thick, minutely 
puberulent with thin mostly retrorse hairs 0.1-0.3 mm 
long, older stems becoming dark brown with rounded 
lenticels ca. 0.4 mm wide; stipules 3-7 mm long, 1.1-2 
mm wide at the base, lanceolate to narrowly triangular, 
venation parallel, reflexed, persisting. Leaves simple, 
petioles 1 .6-10.3 cm long, 0.7-1 .4 mm thick, puberulent, 
with 2 linear stipels at base of blade near petiole attach- 
ment, 0.7-4.3 mm long, 0.2-0.5 mm wide; leaf blades 
6-15 cm long, 4-13 cm wide, ovate to ovate-triangular, 
apex short-acuminate to acuminate, tip 3-10 mm long, 
margin entire or minutely (0.3 mm) denticulate, base 
cordate to subcordate-truncate, drying chartaceous, up- 
per surfaces minutely puberulent on the major veins, 
lower surface with minute puberulence on all the veins, 
venation palmate with 3 major ascending veins and 2 
lesser laterals, 2 veins 1-3/side of midvein. Inflores- 
cences on short (0.5-8 mm) axillary branches, peduncles 
3-18 mm long, 0.6-1 mm thick, minutely puberulent, 
involucral stipules 410 mm long, ovate-triangular; in- 
volucral bracts 15-50 mm long, 18-50 mm wide, ovate 
to ovate-triangular, base cordate, often with a thick (1.3- 
2 mm) petiole 6-1 1 mm long, pinkish or white with 
darker red or purple venation, margin with prominent 
(2-6 mm) teeth, with 5-7 major veins; resin dark purple. 
Male cy mules on peduncles to 1.5 mm long, involucel 
of 4 free broadly imbricate concave bracteoles, 6 flowers 
8-9, pedicels 3-6 mm long, puberulent distally, calyx 
lobes 4, puberulent on exterior, staminal column 2.5- 
3.5 mm long, glabrous, anthers 20-30. Female cymules 
with abaxial bracteoles ca. 5 mm long, concave, glabrous 
with ciliate margin; 9 flowers with 5-1 1 narrow pinna tifid 
sepals with slender lobes, pubescent; ovary densely his- 
pidulous, styles 3-5.5 mm long, stigmas 1.5-4 mm wide, 
rounded, flat and peltate. Fruits 8-10 mm long, 11-16 
mm wide, deeply 3-lobed, sparsely pubescent with hairs 
0.1-0.4 mm long, thick-walled (to 2 mm), subtended by 
sepals 10-16 mm long, central rachis to 1.3 mm wide, 
lateral lobes 4-12 mm long, 0.3 mm wide, hairs ca. 0.4 
mm long, columella 4.5-5 mm long, 4-5 mm wide at 
apex, T-shaped; seeds 4.5-5.8 mm long, 4.5-6 mm wide, 
3.3-4.5 mm thick, lenticular-triangular in cross-section, 
with a distal longitudinal peripheral ridge and 2 parallel 
longitudinal adaxial ridges, slightly rugose. 

Plants of evergreen rain forest formations of the 
Caribbean and southern Pacific slopes at 10-1 100 
m elevation. Flowering and fruiting throughout 
the year. The species ranges from southeastern 
Nicaragua to Peru. 

Dalechampia dioscoreifolia is recognized by its 
simple unlobed cordate leaves, bright pink invo- 
lucral bracts with dark reddish veins against a pal- 
er background, peltate stigmas, fruits subtended 
by narrow sepals with long lateral lobes and sting- 



ing hairs, and unusual seeds with longitudinal ridg- 
es. The involucral bracts often have prominent 
petioles. 



Dalechampia heteromorpha Pax & K. Hoffm., 
Pflanzenreich IV, 147, XII: 26. 1919. D. gua- 
temalensis Gandoger, Bull. Soc. Bot. Fr. 66: 
286. 1920. D. molliuscula Blake, Contr. U.S. 
Natl. Herb. 24: 12. 1922. Figure 5. 

Clambering vines, leafy stems 0.6-1.8 mm thick, with 
thin retrorse whitish hairs 0.1-0.5 mm long; stipules 2- 
6 mm long, 0.6-0.8 mm wide at base, narrowly lanceo- 
late-linear, sparsely puberulent, venation obscure, per- 
sisting or deciduous. Leaves varying on the same stem, 
simple and ovate to 3-foliolate, petioles 1.2-1 1 cm long, 
0.5-1.6 mm thick, sparsely pubescent, stipels often pres- 
ent, 1-4 mm long, ca. 0.4 mm wide, petiolules 0-3 mm 
long; leaf blades of simple leaves 3-14 cm long, 2-8 cm 
wide, narrowly ovate-triangular with cordate or subcor- 
datebase, central blade of 3-foliolate leaves 3-1 1 x 1.4- 
3.2 cm, narrowly elliptic or narrowly elliptic-oblong to 
oblanceolate, apices acuminate, margins denticulate to 
rounded -crenate or subentire, teeth 3-6/cm, base of lat- 
eral leaflets asymmetric and rounded on the outer side, 
drying chartaceous, with thin straight hairs 0.2-1.1 mm 
long (shorter beneath), simple leaves with palmate ve- 
nation and 3 (5) major veins and 2 veins 2-3/side, lateral 
leaflets with 2 major veins, 3 veins subparallel. Inflo- 
rescences on axillary stems 1-5 cm long, peduncles 0.5- 
0.9 mm thick, pubescent, involucral stipules 2-3 mm 
long, 0.4-1 mm wide at base, puberulent; involucral bracts 
1-2 cm long at anthesis and green, becoming 1 6-27 long 
and 16-30 mm wide in fruit, ovate to broadly ovate, 
margin undivided with small (0.2 mm) glandular teeth 
or deeply 3-lobed, sparsely pubescent. Male flowers with 
connate involucellar bracteoles; stamens 20-30 and 
crowded. Female flowers with ca. 1 narrow sepals with 
narrow pinnatifid lobes, with stiff yellowish hairs ca. 1 
mm long; ovary pubescent, stylar column 3-4 mm long, 
slightly expanded at apex. Fruits ca. 6 mm long, 7-10 
mm wide, with 3 rounded lobes, minutely (0.1-0.2 mm) 
puberulent, subtended by the pinnatifid sepals 7-10 mm 
long with narrow (0.5-1 mm) central axis with 3-7 nar- 
row lobes 1-1.4 mm long and stiff sharp hairs 0.8-1.5 
mm long; seeds 3.4-4.3 mm diam., subglobose, mottled 
brown to dark brown, smooth. 

Plants often found in secondary growth in ev- 
ergreen forest areas, 0-1 100 m elevation. Flow- 
ering throughout the year. First collected in Costa 
Rica (Brenes 14414 the type), the species ranges 
from Veracruz, Mexico, to southernmost Puntare- 
nas (but see below). 

Dalechampia heteromorpha is recognized by 
having both ovate-triangular leaves and three-fo- 
liolate leaves (often on the same short length of 
stem) and the linear-oblong 9 sepals with narrow 
pinnatifid lateral lobes and sharp hairs. The lateral 



BURGER & HUFT: FLORA COSTARICENSIS 



107 



leaflets of three-foliolate leaves are asymmetric at 
the base, very much like those of D. cissifolia and 
D. websteri. It seems probable that the plants placed 
here are no more than an unusual form of D. cis- 
sifolia. 

Dalechampia osana Armbruster, Syst. Bot. 1 3: 303- 
312. 1988. Figure 4. 

Clambering vines, leafy stems 3-9 mm thick, hirsute 
with straight orange or yellow hairs 0.7-2 mm long (fad- 
ing to gray), shorter hairs 0.2-0.5 mm long; stipules 7- 
1 4 mm long, 4-9 mm wide near base, ovate or triangular, 
glabrous adaxially, becoming reflexed, persistent. Leaves 
simple, petioles 3-13 cm long, 1-2 mm thick, often ge- 
niculate at the base, pubescent as the stems, with 2 stipels 
at base of blade, 3-5.5 mm long, ca. 0.5 mm wide, gla- 
brous; leaf blades 5-28 cm long, 5-25 cm wide, ovate 
and unlobed to 3-lobed, apices acuminate, margin entire 
to minutely denticulate with pubescent teeth 0.2-0.5 mm 
long, base cordate to subcordate, sinus 5-50 mm deep, 
drying chartaceous, sparsely hirsute with thin hairs above, 
more densely pubescent beneath with hairs 0.5-1 mm 
long, venation palmate with 5 major veins, 2 veins 3- 
4/side of the midvein, 3 veins subparallel. Inflores- 
cences on axillary branches 1 5-40 mm long (subsessile), 
densely pubescent, involucral stipules 7-14 x 6-1 1 mm; 
involucral bracts 1 6-25 mm long, 1 5-20 mm wide, white, 
3-lobed, middle lobe 2-3 mm long, lateral lobes ca. 2 
mm long, narrowed at base and with 3 major veins, 
hirsute with orange/yellow hairs on both surfaces, a dis- 
tinct resin gland present on staminate involucel. Male 
cymules with peduncle 3-4 mm long, involucel with 2 
pairs of decussate free ovate bracts 8-9 mm long, mar- 
gins finely glandular-dentate; <3 flowers 10 (1 terminal 
and 3 3-flowered groups), subtended by 3-4 bracteoles 
34.5 mm long with laciniate and resinous margins; ped- 
icels 3.5-5 mm long, calyx splitting into 3-5 parts ca. 4 
mm long, 1-3 mm wide, lanceolate, staminal column 4- 
6 mm long, ca. 1 mm thick, stamens 25-30, filaments 
ca. 1 mm long, anthers ca. 0.6 mm long. Female cymes 
sessile, subtended by 2 (3) stipule-like bracts with irreg- 
ular denticulate margins, distal (adaxial) bracts 7-9 mm 
long, 6-8 mm wide, overlapped by the proximal (abaxial) 
bracts 10-12 mm wide; $ flowers subsessile at an thesis, 
sepals 5-6, hirsute with orange or yellow hairs, 4-5 mm 
long, ca. 1.5 mm wide, margin with laciniate teeth 0.2- 
0.8 mm long, ovary ca. 2 x 2 mm, stylar column curved 
upward near the base and downward distally, 8-10 mm 
long, 0.9-1.2 mm thick, dilated at tip and 2.5-4 mm 
wide. Fruits 8-10 mm diameter, densely hispid-laciniate 
with orange or yellowish hairs, borne on pedicels 5-7 
mm long (central fruit) or 2 mm long (laterals), persisting 
sepals 10-15 mm long and 3^1 mm wide, lanceolate, 
columella 5.5 mm long; seeds 5x4 mm, ovoid to round- 
ed-oblong. 

Plants of rain forests of the southeastern Pacific 
lowlands, 40-250 m elevation. Flowering in Sep- 
tember-November. This species is endemic to the 
Osa Peninsula. 

Dalechampia osana is recognized by its hirsute 



stems, large ovate to three-lobed leaves, orange or 
yellowish pubescence on young shoots, short flow- 
ering branches, and compact inflorescences. The 
reflexed persisting stipules, glabrous on the inner 
face, are also noteworthy. 

Dalechampia scandens L. Sp. PI. 1054. 1753. Fig- 
ure 4. 

Climbing vines, woody at base, leafy stems 0.7-3.5 
mm thick, densely pubescent with straight hairs 0.4-1 
mm long and minute (0. 1-0.2 mm) appressed hairs; stip- 
ules 3.5-9 mm long, 1.8-2.8 mm wide at base, ovate- 
lanceolate to narrowly triangular, reflexed, persistent. 
Leaves simple but 3-lobed with deep narrow sinuses, 
petioles 1.5-9(-12) cm long, 0.8-1.8 mm thick, densely 
pubescent, stipels 2, l-2(-3) mm long, glandular at base; 
leaf blades 4-13 cm long, 5-16 cm wide, middle lobe 
3-10 cm long, 1.8-5 cm wide, elliptic-oblong to elliptic 
or obovate, apices short-acuminate to obtuse or round- 
ed, margins subentire or minutely (0.2 mm) denticulate, 
base cordate with wide or narrow sinuses 3-17 mm deep, 
lateral lobes asymmetric with wide outer basal area, dry- 
ing chartaceous, with (0. 1-0.7 mm) straight hairs above, 
with shorter denser hairs beneath, venation palmate with 
5 major veins (lateral lobes with 2 major veins), 2 veins 
4-8/side, 3 veins subparallel. Inflorescences 1-2, on ax- 
illary shoots with small (8-12 mm) leaves or leaves not 
developed, peduncles 1-6 cm long, 0.3-0.7 mm thick, 
with thin sharp hairs 0.2-1 mm long (differing in differ- 
ent plants), involucral stipules 5-7 mm long, 1 .5-2.5 mm 
wide at base, ovate-lanceolate to lanceolate, reflexed; 
involucral bracts 1.6-3( 4) cm long, 1.6-3.5( 4.6) cm 
wide, pale green to white, ovate-triangular to ovate-or- 
bicular, 3-lobed at apex, lobes 20-50% of bract length, 
margin with glandular teeth. Male cymules on peduncles 
2.5-3.5 mm long, involucel 2-4 mm high, 6-8 mm wide 
(bracteoles completely connate), $ flowers 9-10, pedicels 
to 1 mm long, buds ca. 2 mm diam., sepals ca. 3 mm 
long, glabrous, becoming reflexed, staminal column ca. 
2 mm long, filaments 0.1-0.2 mm long, anthers 25-35, 
ca. 0.4 mm long. Female cymules sessile, 3-flowered, 
adaxial bracteoles 3-6 mm high, 6-10 mm wide, seri- 
ceous on both surfaces, 9 flowers subsessile at anthesis 
(central pedicel to 1 2 mm long in fruit), calyx lobes 8- 
1 2, unequal, narrow with 3-5 slender gland-tipped lat- 
eral lobes/side; styles 3-8 mm long, often curved, stigmas 
0.5-1.3 mm wide. Fruits 6-7 mm long, 8-9.5 mm wide, 
subtended by 8-12 sepals 5-12 mm long with central 
axis 0.4-0.8 mm wide, edges with sharp hairs ca. 1 mm 
long and/or gland-tipped hairs, columella ca. 3 mm long, 
4 mm wide at apex (T-shaped); seeds 3.6-4.2 mm diam., 
subglobose, smooth, mottled. 

Plants of open sites in deciduous and partly de- 
ciduous formations of the Pacific slope, 10-1000 
m elevation. Flowering in August-September; 
fruiting in October-February. This species is wide- 
spread in the American tropics. 

Dalechampia scandens is recognized by the larg- 
er deeply three-lobed leaves, the usually three-lobed 
involucral bracts, narrow sepals with short narrow 



108 



FIELDIANA: BOTANY 



pinnatifid gland-tipped lobes, and smooth globose 
seeds often with an intricate pattern of strongly 
contrasting dark and light mottling. Stinging hairs 
are usually present, with mala the consequent 
common name. 

Dalechampia shankii (A. Molina) Huft, Ann. Mis- 
souri Hot. Gard. 71: 541. 1984. Tragia shankii 
Molina, Ceiba 1 1: 68. 1965. Figure 4. 

Clambering vines and lianas, leafy stems 2-6 mm thick, 
with yellowish or orange hairs to 1.5 mm long and mi- 
nute (0.1-0.2 mm) appressed hairs; stipules 10-16 mm 
long, 4-6 mm broad at the base, ovate-triangular to ovate- 
lanceolate, glabrous within, venation parallel, persisting 
and recurved. Leaves simple, unlobed or with 1-3 prom- 
inent distal lobes, petioles 4-18 cm long, 1.5-3.5 mm 
thick, pubescent as the stems, 2 adaxial stipels at the 
base of the blade, 2-5.5 mm long, ca. 0.5 mm wide; leaf 
blades 1 1-26 cm long, 9-28 cm wide, ovate to deeply 
3-lobed, central lobe up to 70% of blade length, apex 
acuminate, margin with 6-10 small teeth/cm, base deep- 
ly cordate with sinus 1 .5-8 cm deep, basal lobes usually 
divergent, drying chartaceous, upper surface with slightly 
curved hairs 0.2-0.8 mm long, lower surface with shorter 
(0.2-0.5 mm) hairs on venation, venation palmate with 
5 major veins, 2 veins 2^4/side of the mid vein, 3 veins 
parallel. Inflorescences 1.5-3 cm long, axillary, pedun- 
cles to 8 mm long, involucral stipules ca. 6 mm long, 
reflexed and glabrous within; involucral bracts ca. 1 3 x 
8 mm, densely sericeous with ascending golden-orange 
hairs ca. 1 mm long, distal margin entire; a distinct resin 
gland not developed. Male flowers usually 1 3 on 4 plei- 
ochasial arms, resin gland absent, sepals ca. 3 x 1.2 mm 
and reflexed, glabrescent, staminal column ca. 6 x 0.3 
mm, filaments 0.7-1.2 long, anthers 0.5-0.7 mm long. 
Female flowers with sepals to 1 5 mm long in fruit, with 
lateral teeth ca. 1 mm long; style column ca. 8 x 0.7 
mm, stigma 1 .3-2 mm wide. Fruits 6-8 mm long, ca. 9 
mm wide, densely covered with orange-yellow hairs 0.3- 
1 mm long, columella ca. 4 mm long, 34 mm wide at 
apex; seeds 44.7 mm long, 3.5-4.5 mm wide, subglo- 
bose-oblong, brown, smooth. 

Plants of lowland Caribbean rain forest for- 
mations, 10-200 m elevation. Flowering and fruit- 
ing collections were made in June and December. 
The species ranges from northern Costa Rica to 
Ecuador. 

Dalechampia shankii is recognized by its larger 
leaves and thicker stems, characteristic yellowish 
or orange pubescence, short flowering stems and 
compact inflorescences. Compare D. osana and 
Tragia bailloniana with very similar foliage. 

Dalechampia spathulata (Scheidw.) Baill., Etude 
Euphorb. 487. 1856. Cremophyllum spathulata 
Scheidw., Bull. Acad. Roy. Sci. Bruxelles 9: 23. 
1842. D. roezliana Mull. Arg. in DC., Prodr. 15 
(2): 1233. 1866. Figure 13. 



Erect subshrubs 0.3-1 m tall, stems woody and usually 
unbranched, leafy stems 2-5 mm thick, densely pubes- 
cent with hairs 0. 1-0.2 mm long; stipules 7-12 mm long, 
4-6 mm wide at the base, triangular to lanceolate with 
7-13 parallel veins, minutely and sparsely puberulent, 
persisting. Leaves subsessile or with petioles to 9 mm 
long, 1 .3-2 mm thick, sparsely puberulent, stipels usually 
2, minute; leaf blades 12-28 cm long, 4-10 cm wide, 
oblanceolate or narrowly elliptic-obovate to narrowly 
obovate, apex gradually acuminate or abruptly caudate- 
acuminate, margin entire or with low blunt teeth (1-2 
teeth/cm), base long-cuneate and attenuate, often slightly 
(0.5 mm) auriculate at the petiole, drying thin-charta- 
ceous, glabrous above and below, 2 veins 9-12/side. 
Inflorescences axillary, peduncles 2-4.7 cm long, 0.7-1 
mm thick, minutely puberulent with whitish hairs 0.1 
mm long, involucral stipules ca. 4 mm long; involucral 
bracts 2.5-5 cm long, 2-4 cm wide, ovate-triangular, 
with serrate edge (3-5 teeth/cm), base obtuse to truncate 
(subcordate), rose-red to purple-red or yellow, 3-veined, 
sparsely and minutely puberulent beneath. Male flowers 
usually 9, sepals 6, reflexed, staminal column ca. 3.4 mm 
long, filaments short, anthers ca. 15, 0.7-0.9 mm long. 
Female flowers with 6 linear-lanceolate sepals, ca. 1 mm 
long, style column 5-8 mm long, ca. 0.3 mm thick. Fruits 
5-6 mm long, ca. 9 mm wide, 3-lobed, puberulent, col- 
umella ca. 4 mm long, T-shaped, 2.5-4 mm wide; seeds 
45 mm diam., subglobose, tubercles 0.2-0.5 mm high, 
scattered or some in longitudinal ranks, brown. 

Plants of lowland Caribbean rain forest for- 
mations, 50-600 m (to 1100 m in Mexico) ele- 
vation. Flowering and fruiting in February-June. 
Only a few collections from near Tilaran and Upa- 
la have been made in Costa Rica. The species 
ranges from Veracruz, Mexico, to Peru. 

Dalechampia spathulata is unique among our 
species of Dalechampia with its short erect un- 
branched habit and long subsessile oblanceolate 
leaves. The stiff persisting stipules, colorful in- 
volucral bracts, lack of resin-producing glands, and 
tuberculate seeds are also distinctive. 

Dalechampia tiliifolia Lam., Encycl. 2: 257. 1786. 
Figure 4. 

Clambering vines, leafy stems 1.4-4 mm thick, pu- 
berulent with minute (0.1-0.3 mm) whitish hairs and 
with few longer (ca. 1 mm) straight sharp hairs; stipules 
1.5-9 mm long, 0.3-0.8 mm wide at base, acute, decid- 
uous. Leaves usually 3-lobed (unlobed ovate/cordate 
leaves with 5 palmate veins or 2-lobed leaves sometimes 
present), petioles 1-14 cm long, 0.8-1.8 mm thick, mi- 
nutely puberulent, often geniculate at the base, stipels at 
apex of petiole usually 2-4, 0.3-4 mm long; leaf blades 
4-16 cm long, 4.5-17 cm wide, central lobe more than 
'/2 the length of the blade, obovate to elliptic-obovate, 
apices obtuse to short-acuminate (rounded), margin sub- 
entire or minutely denticulate with 4-6 teeth/cm, base 
cordate with broad sinuses 4-24 mm deep, drying thinly 
chartaceous and grayish green, soft thin hairs (0.2-0.3 
mm long) more dense beneath, venation palmate with 



BURGER & HUFT: FLORA COSTARICENSIS 



109 



3 major veins and 2 minor laterals, 2 veins 3-6/side of 
midvein. Inflorescences on axillary stems with smaller 
(4-8 cm) leaves, peduncles to 3-4 cm long (to 7 cm in 
fruit or apparently longer when subtending leaves fail to 
develop), densely pubescent, involucral stipules 2-7 mm 
long, 0.5-0.8 mm wide, linear-lanceolate; involucral 
bracts 2-5 cm long, 1.7-4.8 cm wide, rounded-ovate, 
with 3 (5) short (2-7 mm) apical lobes, pale greenish 
yellow to white, becoming greenish, with 7-1 1 veins 
from the base, pubescent with thin hairs 0.2-0.5 mm 
long on both surfaces. Male cymules on peduncles 3.5- 
6 mm long, 10-12 mm wide; involucellar bract united 
near base, <5 flowers 9-10, pedicels 4-8 mm long, basal 
part 0.5 mm thick, calyx splitting into 3-6 parts, 2-3.5 
mm long and reflexed; staminal column 2.5-4 mm long, 
androecium rounded and 2.5 mm diam., anthers 25-45, 
0.5-0.8 mm long. Female flowers subtended by bracts 
6-8 mm long, with 9-12 narrow pinnatitid sepals (dif- 
ficult to see at an thesis), the narrow lobes 6-10; ovary 
ca. 4 mm diam., with sharp straight hairs 1-1.5 mm 
long, stylar column 7-12 mm long, 0.3-0.7 mm thick, 
dilated stigmatic apex 1.3-3.5 mm wide. Fruits 7-10 
mm long, 14-16 mm wide, 3-lobed, densely hispid, sub- 
tended by the stiff sepals 8-16 mm long, 0.6-2 mm wide, 
with pinnati fid lobes 0.5-1 .5 mm long and sharp stinging 
hairs to 1-2 mm long, columella ca. 4 mm long; seeds 
4-5 mm long and wide, 3.8-4 mm thick, subglobose and 
slightly laterally compressed, mottled brown, smooth. 

Plants of evergreen or partly deciduous forma- 
tions of the Pacific slope, 0-1000 m elevation. 
Flowering in November-February; fruiting in Jan- 
uary-March. The species ranges from southern 
Mexico to Brazil and Bolivia. 

Dalechampia tiliifolia is recognized by its larger 
deeply three-lobed (or unlobed) leaves, stinging 
hairs, rounded involucral bracts with small distal 
lobes, and the 9-12 narrow sepals with slender 
pinnatifid lobes and many stinging hairs subtend- 
ing the fruit. The fruiting sepals also have minute 
(0.1 mm) gland-like protuberances on their sur- 
faces. This is one of Central America's most com- 
mon species of Dalechampia, but it has been col- 
lected only along the Pacific slope in Costa Rica. 
It is usually found in drier sites than D. dioscoreifo- 
lia and in moister sites than D. scandens (Arm- 
bruster, 1988). 

Dalechampia websteri Armbruster, Syst. Bot. 9: 
272. 1984. Figure 4. 

Clambering vines, leafy stems 0.5-3.5 mm thick, hir- 
sute with thin erect white or yellowish hairs 0.7-2 mm 
long, and with shorter (0. 1-0.2 mm) hairs; stipules 2-1 2 
mm long, 0.3-3 mm wide, lanceolate, with thin hairs 
and inconspicuous glands, persistent and reflexed. Leaves 
palmately 3-foliolate, petioles 2-6 cm long, 0.5-1.2 mm 
thick, pubescent as the stems, petiolules ca. 2 mm long, 
stipels at apex 2-4 mm long, linear; leaflet blades 6-12 
cm long, 1 .5-4.5 cm wide, middle leaflet narrowly ovate- 
elliptic to elliptic-oblong, lateral leaflets asymmetric with 



base rounded on outer side and cuneate on the inner 
side, apices acute to acuminate, margins glandular den- 
ticulate to sinuate, drying chartaceous, with slender 
slightly curved hairs 0.5-1.5 mm long above, hairs 0.2- 
0.3 mm long on the veins beneath, 2 veins 4-6/side of 
middle leaflet, lateral leaflets with an arcuate lateral vein 
from the base. Inflorescences on leafy lateral stems 10- 
18 cm long, involucral stipules of proximal bract 10-14 
mm long, 3-5 mm wide, stipules of distal bracts similar 
but broader, hirsute-sericeous; involucral bracts sub- 
equal, 2.5-4 cm long, 2-3.5 cm wide, 3-lobed, middle 
lobe 1.5-2 cm long, narrowed to base and 3-4 mm wide, 
palmately 3-veined, white or pale green, resin gland 1 4- 
25 mm long. Male cymules with peduncles 2.5-5 mm 
long, 1.5-2 mm thick, involucel of 4 free decussate brac- 
teoles, 5-6 x 4-6 mm, parallel-veined; $ flowers 10(1 
terminal + 3 groups of 3), subtended by linear or spat- 
ulate bracteoles 4-5 mm long, margins fimbriate, pedi- 
cels 6-10 mm long; <5 flowers usually with calyx splitting 
into 4 ovate-acute parts 1-2.5 mm long, 0.7-1.5 mm 
wide, staminal column ca. 2.5 mm long, anther cluster 
ca. 2 mm wide. Female cymules sessile, involucel of 2 
parallel-veined glabrescent bracteoles, abaxial bracteoles 
4-5 mm long, 5-7 mm wide, simple, adaxial bracteoles 
2-3 mm long, 4-6 mm wide, bilobed; 2 flowers 3, sub- 
sessile at anthesis, sepals 6, 3-5 mm long, 1-2 mm wide, 
laciniate with gland-tipped teeth 1-2 mm long, ovary 
1.5-3 mm long, 1.5-4 mm diam., minutely papillate- 
puberulent to strigulose, stylar column 6-14 mm long, 
0.5-1 mm thick distally. Fruits ca. 8 mm long, 12-14 
mm wide, deeply 3-lobed, subtended by sepals 6-1 2 mm 
long, 1-2 mm wide, with marginal teeth 1-3 mm long 
(often minutely gland-tipped), columella ca. 4.5 mm long; 
seeds ca. 4 mm long, ca. 4.5 mm diam., subglobose. 

Plants of lowland Caribbean rain forest for- 
mations, 5400 m elevation. Flowering and fruit- 
ing in January-October. The species ranges from 
northern Costa Rica to central Panama. 

Dalechampia websteri is recognized by its three- 
foliolate leaves with very asymmetric (at the base) 
lateral leaflets sometimes broader than the narrow 
central leaflet. This species is common at La Selva. 



Drypetes Vahl 

Trees or shrubs, dioecious (rarely monoecious), gla- 
brous or with simple hairs, shoot apex sometimes with 
bud scales; stipules lateral, small, usually caducous. Leaves 
alternate, simple, short-petiolate, blades often slightly 
unequal at the base, often subcoriaceous, pinnately veined, 
margins entire or dentate. Inflorescences axillary or at 
older leafless nodes, unisexual, sessile fascicles of few 9 
or up to 153 flowers, $ flowers sessile or pedicellate, 2 
flowers pedicellate. Male flowers with 4-5 (6-7) imbri- 
cate sepals, concave and often unequal, ciliate, petals 
absent, intrastaminal disk annular or lobed to laciniate; 
stamens 4-1 2 (3-50), filaments free, anthers usually ovate, 
basifixed, extrorse to introrse; pistilode absent or minute. 
Female flowers with 45 (6-7) imbricate deciduous se- 
pals, petals absent, staminodes absent, disk cupulate or 
annular (rarely absent); ovary with 1-2 (3-4) locules, 



110 



FIELDIANA: BOTANY 



usually pubescent externally, ovules 2/locule, styles short 
or absent, stigmas 1-2 (3-4), thick and flattened, entire 
or sometimes bifid. Fruits drupaceous, indehiscent, glo- 
bose to ellipsoid or ovoid, exocarp fleshy or leathery 
(drying hard), 1 -seeded by abortion (sometimes 2-seeded); 
seed ecarunculate, testa smooth, endosperm carnose, 
embryo broad and flat. 

A pantropical genus of ca. 200 species, with ca. 
20 in the American tropics. Fruiting specimens 
are difficult to recognize as Euphorbiaceae, be- 
cause the fruits are indehiscent, one- or two-seed- 



ed, and usually with sessile undivided stigmas. In 
addition, the flowers and flower fascicles are small 
and inconspicuous, resulting in a paucity of col- 
lections. A helpful characteristic in determining 
herbarium material is the tendency of at least some 
leaves to be slightly asymmetric at the base, with 
one side more rounded than the other. Dr. Geof- 
frey A. Levin (ILLS) is studying the American rep- 
resentatives of this genus, and we thank him for 
his annotations and advice. 



Key to the Species of Drypetes 

la. Mature fruits 1-15 mm diam., on slender pedicels ca. 1 mm thick; stigmas 1 or 2 and borne on the 
narrow stylar column; leaves 1 .64 cm wide, usually narrowly oblong to lanceolate; partly deciduous 

or evergreen forest formations 2 

Ib. Mature fruits 14-28 mm diam., on stout pedicels 1.5-2 mm thick; stigmas 1 and sessile on the apex 
of the ovary; leaves 3-8 cm wide, usually oblong to elliptic-oblong; evergreen forest formations 

3 

2a. Locules and stigmas 2/fruit, fruits usually symmetric with the stigma apical; leaves with 3 and 
4 veins not clearly differentiated but elevated and demarking small (0.3-0.9 mm) areas in an 
irregular reticulum, often drying pale grayish; 900-1200 m elevation in partly deciduous forests 

D. laterifolia 

2b. Locules and stigmas 1 /fruit, fruits often distally asymmetric, the stigma often somewhat lateral; 
leaves with 3 and 4 veins better differentiated, often paralleling the secondary veins, not 
forming a reticulum of small areas, drying grayish to dark olive green; 0-800 m elevation in 

evergreen or deciduous areas D. sp. aff. D. alba 

3a. Fruits usually narrowed at the apex, unilocular; leaves with petioles 4-1 5 mm long; mostly collected 

at 200-800 m elevation D. standleyi 

3b. Fruits usually rounded at the apex, bilocular (but may be difficult to see); leaves with petioles 3-8 
mm long; 10-1400 m elevation D. brownei 



Drypetes brownii Standl., Trop. Woods 20: 20. 
1929. Figure 27. 

Trees 5-20 m tall, trunks to 45 cm diam., leafy stems 
1.24 mm thick, glabrous, often with prominent lenti- 
cels; stipules minute (0.5 mm) or obscure. Leaves with 
petioles 3-8 mm long, 0.9-2 mm thick, glabrous, sulcate 
above; leaf blades 9-20 cm long, 3.5-8 cm wide, oblong 
or elliptic-oblong to ovate-oblong, apex acuminate or 
acute with slightly thickened (glandular) tip, margin en- 
tire or slightly undulate, base obtuse to acute, often slightly 
asymmetric, drying subcoriacious and usually grayish, 
glabrous above and below, 2 veins 5-9/side. Male in- 
florescences axillary, few-flowered fascicles, pedicels 3- 
5 mm long, densely minutely sericeous; 6 flowers with 
sepals 3-3.5 mm long, broadly ovate with rounded apex, 
minutely sericeous; stamens 8-12. Female inflorescences 
axillary, fascicles of 1-3 flowers, pedicels 2-4 mm long, 
0.7-0.8 mm thick, sparsely to densely appressed puber- 
ulent with hairs ca. 0.1 mm long; 9 flowers with calyx 
2-3 mm long, lobes 1-2 mm long, ca. 2 mm wide at 
base; ovary 1-2 mm long, 1.2-2 mm diam., broadly 



sessile and ovoid, densely velutinous, stigmas sessile and 
broadly rounded, flat or reflexed, ca. 0.7 mm long, to 
1.8 mm wide. Fruits 13-28 mm long, 12-25 mm diam., 
obovoid to subglobose, rounded apically, surface mi- 
nutely puberulent, bilocular, 1- or 2-seeded; seed ca. 1.5 
mm long. 



A species of evergreen forest formations, from 
near sea level to 1 500 m elevation. Flowers were 
collected in February and May; fruits were col- 
lected in February, April, July, and September. 
This species ranges from Chiapas, Mexico, and 
Belize to western Panama. 

Drypetes brownii is recognized by the stiff gla- 
brous short-petiolate leaves, axillary fascicles of 
few flowers, and obovoid to subglobose one- to 
two-seeded fruits on prominent pedicels. The leaf 
blades are often asymmetric at the base, and the 



BURGER & HUFT: FLORA COSTARICENSIS 



111 



2 veins are strongly ascending. An unusual col- 
lection from near Palmar Norte (Hammel & Agui- 
lar 18193) has larger (32 mm long) pyriform fruits 
with woody endocarp. 



Drypetes lateriflora (Sw.) Krug & Urban, Hot. 
Jahrb. Syst. 15: 357. 1892. Schaefferia lateri- 
flora Sw., Prodr. 329. 1788. Figure 27. 

Trees 6-20 m tall, trunk to 35 cm diam., leafy stems 
0.9-3.5 mm thick, glabrous (rarely minutely puberulent 
at the nodes), grayish; stipules 0.4-1 mm long, triangular 
or obscure. Leaves with petioles 3-10 mm long, 0.6-1.2 
mm thick, glabrous, sulcate above; leaf blades 410 cm 
long, 1.54 cm wide, lanceolate to narrowly ovate-ellip- 
tic or oblong-lanceolate, apex bluntly acute or acumi- 
nate, margin minutely dentate with 1-3 teeth/cm or 
slightly undulate and entire, base acute and often asym- 
metric, drying grayish and stiffly chartaceous, glabrous 
above and below, 2 veins 5-8/side, weakly or irregularly 
loop-connected distally. Male inflorescences axillary, 
sessile fascicles of 5-15 flowers on pedicels 1.5-3 mm 
long, slightly puberulent; $ flowers ca. 3 mm wide, sepals 
4, ca. 1.5 x 1.3mm, minutely puberulent on the exterior, 
broadly imbricate in bud; stamens ca. 4, anthers 0.4-0.8 
mm long, ca. 0.6 mm wide. Female inflorescences ax- 
illary, fascicles of 1-4 flowers/axil, pedicels 4-1 1 mm 
long (to 1 6 mm in fruit), ca. 0.4 mm thick, glabrous; 9 
flowers with 4 sepals 2-3 mm long, triangular, ovary 2- 
3 mm long, 1.6-2 mm diam., ovoid-oblong, densely ve- 
lutinous, style column 0.7-1 mm long, style branches 
(stigmas) to 1 mm long broad and flat. Fruits 1 2-1 5 mm 
long, 1 1-15 mm diam., subglobose or irregular in shape 
(ellipsoid), becoming red-orange at maturity with a soft 
juicy rind, surface minutely (0. 1-0.2 mm) velutinous, 1- 
or 2-seeded. 



Drypetes sp. aff. D. alba (G. Levin, pers. comm., 
Jan. 1994). 

Trees 6-15 m tall, leafy stems 1-2.5 mm thick, gla- 
brous or sparsely minutely puberulent; stipules ca. 0.5 
mm long, triangular. Leaves with petioles 3-9 mm long, 
0.3-1 mm thick, subglabrous, drying dark; leaf blades 
412 cm long, 1.54.5 cm wide, lanceolate to narrowly 
oblong or elliptic-oblong, gradually narrowed to the acu- 
minate apex, margins entire or minutely crenulate, base 
usually somewhat asymmetric, drying stiffly charta- 
ceous, grayish to dark olive green, glabrous, 2 veins 6- 
9/side. Inflorescences with flowers not seen, axillary, fruits 
2-6/node, pedicels 8-12 mm long, 0.4-0.8 mm thick, 
glabrous and drying dark. Fruits 1 1-16 mm long, 8-1 1 
mm diam., ellipsoid to obovoid, often asymmetric dis- 
tally with the style somewhat lateral, surface glabrous 
(but see below). 

Plants of evergreen forests or from moist situ- 
ations in deciduous formations, 0-750 m eleva- 
tion. Fruiting material was collected in March near 
Quepos (Grayum 6614), April near Upala (Her- 
rera 1693), and in June below Monte verde (Bella 
et al. 35 & 58, Hammel & Trainer 17046). 

Drypetes sp. aff. D. alba is recognized by its 
usually narrow leaves often drying dark, general 
lack of pubescence, and narrowly obovoid fruits 
borne on slender pedicels and asymmetric distally. 
This material is rather similar to D. lateriflora, 
which grows at slightly higher elevations in some 
of the same forests, but the fruits and the leaf 
venation are different. The Herrera collection (see 
above), with densely pubescent fruits and elliptic 
leaves, is tentatively included here. 



Plants of partly deciduous tropical moist forest 
of the Pacific slope, 900-1300 m elevation. Flow- 
ering in November-December; fruiting in late Jan- 
uary-July. In Costa Rica, this species has been 
collected on the western slopes of the Cordillera 
de Tilaran in the upper Rio Guacimal drainage, 
Puntarenas Province. The species ranges from 
southern Mexico to Costa Rica and occurs in Flor- 
ida (U.S.A.) and the West Indies. 

Drypetes lateriflora is recognized by the smaller, 
glabrous, leaves that dry pale grayish, the small 
fasciculate flowers, the rounded fruit with mi- 
nutely velutinous surface, and its restricted range 
in Costa Rica. The leaves are often quite asym- 
metric at the base with one side more cuneate than 
the other. We follow the determinations of Geof- 
frey Levin, who has tentatively adopted a broad 
circumscription for this species. This species is 
easily confused with the following (q.v.). A com- 
mon name in Costa Rica is azulillo. 



Drypetes standleyi Webster, Madrono 24: 65. 1 977. 
Figure 27. 

Trees, 1 5-30 m tall, trunks to 1.2m thick, leafy stems 
1.5-4 mm thick, very minutely (0.05-0.1 mm) puber- 
ulent or glabrous, terete, lenticellate; stipules to 1 mm 
long or obscure, caducous. Leaves with petioles 4-10(- 
16) mm long, 1-1.4 mm thick, glabrous, drying dark, 
sulcate above; leaf blades 7-16(-19) cm long, 2.5-6(-7) 
cm wide, oblong-elliptic to elliptic or broadly elliptic, 
apex acuminate, margin entire (subentire), base obtuse 
and often slightly asymmetric, drying grayish or dark, 
subcoriaceous, glabrous above and below or with a few 
hairs along the midvein below, 2 veins 6-9/side, irreg- 
ularly loop-connected near the margin. Male inflores- 
cences axillary, fasciculate with ca. 10 flowers, pedicels 
6-1 1 mm long, 0.3-0.4 mm thick, glabrous; 6 flowers 
with 4 sepals, 2.5-4 mm long, 1.7-2.2 mm wide, ovate 
to ovate-oblong, rounded to acute at apex, sparsely pu- 
berulent externally, ciliate along the edge, glabrous or 
with few hairs within, imbricate becoming recurved, disk 
1-1.5 mm wide; stamens usually 8 (6, 9) in 2 series, 2.5- 
3 mm long, anthers 1.2-1.6 mm long, pistillode absent. 
Female inflorescences axillary, fasciculate with usually 



112 



FIELDIANA: BOTANY 



2 (1-5) flowers on thick pedicels 3-5 mm long, to 13 
mm long in fruit; $ flowers with 4 sepals, 2.8-4.4 mm 
long, 2.5-3.2 mm wide, minutely strigose externally, gla- 
brous within, margin ciliate, disk 2-2.3 mm in diameter, 
puberulent; ovary ca. 2 mm diam., densely velutinous 
or sericeous, style branches (stigmas) ca. 1 mm long, 1.5- 
2.5 mm wide, flat, sessile. Fruits 2-3 cm long, 1.3-1.8 
cm diam., ovoid to ellipsoid, apex acute or rounded, 
usually densely velutinous, persisting stigmas borne on 
a short (1 mm) narrowed tip; seed with woody endocarp 
ca. 1.5 mm thick. 

An uncommon species of evergreen or partly 
deciduous forest formations on both the Carib- 
bean and Pacific slopes, (50-)20Q-700 m elevation 
in Costa Rica. Flowering in May; fruiting in March- 
July in Costa Rica (July-August in central Pana- 
ma). The species ranges from northern Costa Rica 
to western Venezuela. 

Drypetes standleyi is recognized by the stiff gla- 
brous leaves, few axillary fasciculate flowers, and 
fleshy fruit puberulent on the exterior with single 
seed enclosed in a woody endocarp. The leaf blades 
are often asymmetric at the base with one side 
more cuneate than the other. The leaves often have 
several larger 3 veins arising from the midvein 
between the 2 veins and parallel with them; this 
feature may help to separate sterile material from 
that of D. brownii. 



Dysopsis glechomoides (A. Rich.) Mull. Arg. in 
DC, Prodr. 15 (2): 949. 1866. Hydrocotyle gle- 
chomoides A. Rich., Monogr. Hydrocotle 14, t. 
58, f. 17. 1820, Ann. Gen. Sci. Phys. 4: 180. 
1820. Figure 10. 



Decumbent or prostrate herbs, 5-20 cm tall, stems 
0.4-1.5 mm thick (dried), slightly succulent in life, 
sparsely to densely puberulent with thin curved whitish 
hairs 0.1-0.7 mm long; stipules ca. 1 mm long, 0.5 mm 
wide at the base, narrowly triangular, thin translucent. 
Leaves with petioles 6-22 mm long, 0.3-0.4 mm thick, 
with short thin curved hairs; leaf blades 7-25 mm long, 
8-23 mm wide, ovate to ovate-triangular, apex rounded 
with a minute glandular tip, margins with 3-7 rounded- 
crenate lobes/side, sinuses 0.3-1 mm deep, base obtuse 
to truncate, drying membranaceous and gray-green, up- 
per surface with scattered straight sharp- tipped hairs 0.4- 
1.3 mm long, lower surface more densely pubescent with 
shorter hairs, venation subpalmate with 2-4 major 2 
veins/side, arising from the proximal half of the midvein. 
Male flowers on pedicels 6-42 mm long, 0.2-0.3 mm 
thick, sparsely puberulent, sepals 0.8-1 mm long; stami- 
nal column ca. 1 mm long, anthers 0.5 mm long. Female 
flowers on pedicels ca. 1 mm long, sepals 0.6-1 mm long, 
ovary ca. 1 x 1.5 mm, bilobed, sparsely puberulent, 
styles ca. 0.5 mm long. Fruits 1.4-1.7 mm long, 2-2.3 
mm wide, borne on a short (0.2 mm) stipe above the 
persisting sepals, surface with slender slightly curved hairs 
ca. 0.5 mm long; seeds 1.2-1.5 mm long, 0.8-1.2 mm 
diam., subglobose, smooth, lustrous, brownish black. 



Dysopsis Baillon 

Weak-stemmed herbs with slightly succulent stems, 
monoecious, pubescent with simple and multicellular 
hairs; stipules paired at the leaf base, minute, subulate, 
caducous. Leaves alternate, simple, pubescent, petiolate, 
without glands, ovate to subreniform, margins of the 
blades with broadly rounded lobes, membranaceous, ve- 
nation subpalmate with strongly ascending secondary 
veins, major veins terminating in small marginal glands. 
Inflorescences of solitary or few axillary flowers at distal 
nodes, $ flowers with long slender pedicels, 9 flowers on 
short pedicels, bracts minute. Male flowers with 3 nar- 
row minute sepals, apparently valvate in bud, united 
near the base, petals and disk absent; stamens 3 or 6 in 
2 whorls, filaments connate at base, often unequal, an- 
thers ellipsoid, with stiff thecae; pistillode absent. Female 
flowers with 3 narrow sepals, subvalvate in bud, petals 
absent, disk absent; ovary 3-lobed and 3-locular, ovules 
1/locule, styles 3. Fruits capsular, breaking into 3 thin 
2-valved cocci; seeds subglobose, ecarunculate, surface 
smooth. 

Distinguished by its weak herbaceous habit, thin 
alternate leaves, very small solitary axillary flow- 
ers, and thin capsular fruit. This genus is repre- 
sented by a single variable species. 



Understory herbs of wet evergreen montane for- 
ests, 2100-3000 m elevation. Fertile collections 
have been collected in March-April and Septem- 
ber in Costa Rica. The species has been collected 
on Volcan Barva and the Cordillera de Talamanca; 
it ranges disjunctly through the Andes from Co- 
lombia to Chile, with a subspecies on the Juan 
Fernandez Islands. 

Dysopsis glechomoides is recognized by its weak 
herbaceous habit, thin pubescent broadly ovate 
leaves with rounded-crenate margin, subpalmate 
venation ending in marginal glands, minute axil- 
lary flowers, and high-elevation habitat. These 
plants resemble some species of Pilea (Urticacae) 
and Hydrocotyle (Apiaceae). The small flowers are 
probably difficult to see and may account for the 
paucity of collections. 



Euphorbia Linnaeus 

REFERENCE R. Oudejans, World Catalogue of 
Species Names Published in the Tribe Euphor- 
bieae (Euphorbiaceae) with Their Geographical 
Distribution. Oudejans, Utrecht, 444 pp. 1990. 



BURGER & HUFT: FLORA COSTARICENSIS 



113 



Herbs, shrubs, or trees, monoecious (rarely dioecious), 
with milky white sap (often caustic), glabrous or with 
simple hairs, with succulent green stems in some species; 
stipules absent or present, often reduced or gland-like, 
modified as spines in some succulents. Leaves alternate, 
opposite or whorled (sometimes on the same plant), early 
caducous in some succulent species, simple, usually pet- 
iolate, entire or rarely lobed or serrate, glabrous or pu- 
berulent, venation usually pinnate (veins not sheathed 
by chlorenchyma). Inflorescences terminal or axillary, 
made up of 1 to many flower-like cyathia in fasciculate 
to cymose or paniculate arrangements, often subtended 
by opposite reduced leaves, glabrous or puberulent, op- 
posite bracts subtending or adnate to the cyathium or 
absent. Cyathia (singular: cyathium) flower-like struc- 
tures with a campanulate to obconic or tubular cup with 
usually 5 lobes on its distal edge, 4-5 (1,2) nectar glands 
alternating with the lobes, the glands with or without 
broad thin petaloid appendages, bisexual or <5; $ flowers 
usually in 4-5 reduced cymules opposite the lobes within 
the cyathium, the cymules with or without subtending 
bracteoles; cyathium with a single central ("terminal") 
9 flower. Male flowers reduced to solitary naked stamens 
in congested cymules of 1-5 stamens within the cy- 
athium, each stamen representing a single $ flower and 
borne on a slender stipe (= pedicel, appearing as the base 
of an articulated filament), a reduced calyx rarely present 
at the apex of the stipe; anther often with 2 divergent 
subglobose thecae; pistillode absent. Female flowers sol- 
itary within the cyathium, sessile or stipitate (pedicel- 
late), perianth usually absent (rarely with 3 rudimentary 
sepals or a minute calyx cup at the apex of the stipe), 
stipe (pedicel) often elongating in fruit; ovary 3-locular 



(rarely 2, 4, or 5), ovules 1/locule, styles 3 (2, 4, 5), free 
or united near the base, usually bifid distally. Fruits cap- 
sules (schizocarps, rarely drupaceous) with 3 (rarely 2, 
4, or 5) 2-valved cocci, often dehiscing explosively, col- 
umella usually persisting; seeds ovoid to terete, with a 
longitudinal adaxial raphe, surface smooth or pitted to 
tuberculate, with or without a caruncle, embryo straight, 
cotyledons flat. 

Euphorbia is one of the largest genera of plants, 
with more than 1 ,000 species, and .is extremely 
diverse vegetatively. It is found in all but the coldest 
climates, with greatest diversity in the tropics and 
subtropics. The genus is especially speciose in dry- 
er regions; it is poorly represented in lowland rain 
forest formations. The shrubby and tree-like spe- 
cies are all tropical or subtropical. The cactus-like 
succulent species are native to the African region 
and extending to Arabia and India, with a few in 
South America. The latex is often strongly caustic, 
and the plants are often free of herbivory. The 
cyathium is a unique flower-like structure, appar- 
ently evolved by the fusion of bracts subtending 
an inflorescence of 4 or 5 reduced 6 cymules and 
a terminal 9 flower. Note that Chamaesyce species 
have the same cyathial structure and are consid- 
ered species of Euphorbia subgenus Chamaesyce 
by many taxonomists. 



Key to the Species of Euphorbia 

la. Plants cultivated for ornament or used to make hedges and fences; not known to be naturalized 

in Costa Rica 2 

Ib. Plants growing wild in natural vegetation or as weeds in cultivated land (hedgerow plants in E. 

hqffmanniana) 7 

2a. Stems with longitudinal ranks of sharp paired spines, distal stems quickly becoming > 1 cm 

thick 3 

2b. Stems lacking longitudinal ranks of sharp spines, distal stems usually < 1 cm thick ... 4 
3a. Spines 8-18 mm long, stems hard and woody; inflorescences with peduncles 3-7 cm 

long; cyathia with 2 adnate petal-like bracteoles usually red or pink in color 

E. splendens 

3b. Spines 14 mm long, stems succulent; inflorescences subsessile; cyathia subtended by 

free bracteoles, not brightly colored E. neriifolia 

4a. Inflorescences subtended by colorful (red, pink, white) leaves 5-22 cm long; small shrubs 

E. pulcherrima 

4b. Inflorescences not subtended by such large or colorful leaves; shrubs and small trees . . 5 
5a. Plants leafless or with caducous leaves, stems mostly vertical, terete and green; many-branched 

shrubs and trees E. tirucalli 

5b. Plants with colorful leaves, stems spreading and vertical, not terete and green 6 

6a. Inflorescences with narrow white bracteoles to 15 mm long; leaves elliptic to oblong, 0.7-3 
cm wide, pale greenish or greenish white E. leucocephala 



114 



FIELDIANA: BOTANY 



6b. Inflorescence with linear green to purple bracteoles to 3 mm long; leaves ovate-triangular to 

suborbicular, 3-9 cm wide, green to dark purple or reddish E. cotinifolia 

7a. (from Ib) Leaf blades 15-50 cm long, narrowly obovate-oblong; cyathia 4-5 mm long on dichot- 

omous branches of long-pedunculate inflorescences; evergreen forests E. elata 

7b. Leaf blades < 12 cm long, variously shaped; cyathia 0.5-3 mm long; deciduous and evergreen 

vegetation 8 

8a. Cyathium with a single marginal gland (rarely 2); leaves subtending inflorescences usually pale- 
colored or with colorful spots, leaf blades often pandurate in shape with 2 lateral lobes separated 

by a rounded sinus; small (< 1 m) plants of open weedy sites [seeds tuberculate] 9 

8b. Cyathium with 2-5 marginal glands; leaves subtending the inflorescences not brightly colored or 
with colored spots, leaf blades never pandurate in shape; small or large plants of open or forested 

sites 10 

9a. Gland of the cyathium tubular or cup-shaped, rounded distally; leaves subtending the inflo- 
rescences green spotted with white or purple near the base; seeds angulate in cross-section, 

coarsely tuberuculate E. heterophylla 

9b. Gland of the cyathium transversely oblong and bilabiate; leaves subtending the inflorescences 
green with red markings at the base or red throughout; seeds rounded in cross-section, finely 

and sharply tuberculate E. cyathophora 

1 Oa. Plants herbs or subshrubs, rarely > 1 m tall; leaves on stems alternate, opposite or alternate distally; 

seeds often with conspicuous pits or papillae 11 

lOb. Plants shrubs and small trees, 0.5-5 m tall; leaves opposite, whorled or alternate; seeds various 

16 

11 a. Largest leaf blades usually < 15 mm long (rarely 20 mm), length and width often almost 

equal, petioles filiform, to 0.3 mm thick when dried; seeds 0.9-1.1 mm long 

E. ocymifolia 

lib. Largest leaf blades usually > 20 mm long, clearly longer than wide, petioles 0.3-1.4 mm 

wide when dried; seeds 1-3 mm long 12 

1 2a. Seeds smooth, without pits or papillae; plants found only on Cerro Horqueta, Panama [cyathia 

with 4 glands] E. dwyeri 

1 2b. Seeds with a pitted or papillate surface 13 

13a. Seeds 2.5-2.9 mm long, with a surface of raised papillae; cyathia usually with 2 large glands 
(smaller glands sometimes present) [fruits minutely puberulent; leaves broadly ovate to ovate- 
lanceolate; 0-2500 m elevation; rarely collected] E. oerstediana 

13b. Seeds 1-2 mm long, with well-defined depressions separated by elevated ridges; cyathia with 
4-5 glands (if naturalized E. peplus with many narrowly obovate leaves 6-25 mm long will 

key here) 14 

14a. Capsules puberulent; seeds 1.1-1.5 mm long; distal leaves ovate-elliptic to narrowly elliptic; 

rarely collected, 1 500-2000 m elevation in southern Central America E. xalapensis 

14b. Capsules glabrous; seeds 1.4-1.7 mm long; distal leaves narrowly elliptic to linear-oblong; 

commonly collected between 20 and 1 600 m elevation 15 

15a. Cyathia with 1 petaloid appendage/gland, to 0.5 mm broad (usually 5/cyathium); distal leaf 

blades often long and narrow E. graminea 

1 5b. Cyathia with 2 narrow petaloid appendages/gland, ca. 0.2 mm wide (to 1 0/flower); leaf blades 

often ovate to oblong E. segoviensis 

1 6a. (from 1 Ob) Cyathia usually solitary and tightly enclosed within an involucre of imbricate bracteoles, 
nearly all axillary, sometimes on leafless stems in January-March; seeds 2.2-2.5 mm long, minutely 

tuberculate; 1 100-2100 m elevation E. hoffmanniana 

16b. Cyathia 1-3 or more, not enclosed within an involucre of bracteoles, axillary or terminal, on leafy 
or leafless stems; seeds 3-3.5 mm long, rugulose with irregular ridges and depressions; 10-1300 

m elevation 17 

1 7a. Leaves usually 4/node, ovate-suborbicular, petioles 1 3-40 mm long, slender; capsules glabrous 

E. schlechtendalii 

17b. Leaves usually 2-3/node, ovate-oblong, petioles 5-10 mm long; capsules puberulent 

. E. colletioides 



BURGER & HUFT: FLORA COSTARICENSIS 1 1 5 



Euphorbia colletioides Benth., Hot. voy. Sulph. 1 63. 
1 846. Aklema colletioides (Benth.) Millsp., Publ. 
Field Columb. Mus., Bot. Ser. 2: 416. 1916. 
Figure 30. 

Shrubs or small treelets l-2(-3) m tall, branches some- 
times clambering, nodes somewhat thickened and artic- 
ulate, leafy stems 1-3 mm thick, glabrous, terete, inter- 
nodes 2-5 cm long, becoming very dark; stipules absent, 
transverse or round glands 1-1.7 mm wide often present 
below or between the leaf bases. Leaves 2-3/node, pet- 
ioles 5-9 mm long, 0.4-0.9 mm wide, glabrous or sparse- 
ly and minutely puberulent with whitish hairs ca. 0.2 
mm long; leaf blades 22-45 mm long, 8-23 mm wide, 
oblong to elliptic-oblong or narrowly ovate-oblong, 
bluntly obtuse to rounded at the apex, margin entire, 
obtuse to acute at the base, drying chartaceous, glabrous 
(minutely puberulent in early stages), 2 veins 5-1 I/side. 
Inflorescences terminal or axillary, often borne at leafless 
nodes, 5-10 mm long, dense fascicles of short cymes, 
peduncles 1-5 mm long, bracts ca. 1 mm long, caducous. 
Cyatbia 2-3 mm long, 1.5-2 mm wide, obconic to cam- 
panulate, sparsely to densely minutely whitish puberu- 
lent externally with minute (0.1-0.2 mm) whitish hairs, 
glands with petaloid lobes 1 x 1.3 mm; anthers 0.7 mm 
wide with opposed thecae; stipe 4-6 mm long, ca. 0.3 
mm thick, styles 1 mm long. Fruits ca. 4 mm long, ca. 
4.7 mm wide, sparsely and minutely puberulent; seeds 
3.2-3.3 long, 2.1-2.3 mm diam., oblong with truncated 
base, surface wrinkled-rugulose with irregular pits and 
depressions. 

Plants of rocky terrain in seasonally very dry 
deciduous forest formations, 0-200 m elevation 
(to 800 m in Nicaragua). Probably flowering pri- 
marily at the end of the wet season (December- 
February). In Costa Rica, this species is known 
only from near the Pacific coast in Sta. Rosa Na- 
tional Park. The species occurs in Mexico, Nica- 
ragua, and northwestern Costa Rica. 

Euphorbia colletioides is recognized by its small 
opposite or whorled leaves on stems that become 
dark and smooth, small dense mostly axillary in- 
florescences, and seeds with unusual surface. 

Euphorbia cotinifolia L., Sp. PL 453. 1753. Figure 
30. 

Shrubs or small trees 2-6(-10) m tall, with a rounded 
crown, sap very caustic, leafy stems 0.4-6 mm thick, 
glabrous or with thin whitish hairs ca. 0.2 mm long, 
terete, nodes thickened; stipules poorly developed. Leaves 
usually 3 (2) at each node, petioles 2-6(-9) cm long, 0.3- 
1 mm thick, glabrous; leaf blades (2-)4-9(-l 1) cm long, 
(1.5-)2.5-7(-9) cm wide, broadly ovate-triangular to 
ovate-suborbicular or broadly elliptic, apex bluntly ob- 
tuse to rounded, margins entire, base rounded to trun- 
cate, drying membranaceous to thinly chartaceous, dark 
grayish green to deep purple, glabrous or sparsely pu- 
berulent beneath, 2 veins 8-12/side. Inflorescences ter- 
minal or axillary, 1-4 cm long or becoming large com- 



pound cymose leafy panicles to 30 cm long with 2- or 
3-branched nodes, minutely puberulent. Cyathia ca. 2 
mm long, 2-4 mm diam. distally, sparsely puberulent 
on the exterior, glands 0.3-1 mm long, ca. 1.3 mm wide, 
petaloid extensions 0.5-1.5 mm long, 1-2 mm wide, 
white; stamens red, anthers ca. 0.7 mm wide, thecae 
rounded and divergent; styles ca. 1.2 mm long, thick. 
Fruits ca. 4 mm long, 4-5 mm wide, oblong-rounded 
and 3-lobed, surface glabrous or minutely puberulent, 
columella 3-3.5 mm long, widened distally; seeds 2.5- 
3 mm long, ca. 1 .7 mm diam., surface wrinkled or pitted. 

Euphorbia cotinifolia is recognized by the 
rounded dark red to purple leaves on long thin 
petioles. While frequently seen in gardens and 
hedgerows, this species is not known to be natu- 
ralized in Costa Rica. It is grown primarily in ev- 
ergreen and partly deciduous areas (0-1400 m) and 
is deciduous in the dry season. The sap is extreme- 
ly caustic (Standley & Steyermark, 1949, p. 97). 
The plant is called barrabas in southern Central 
America; Pittier cites horla as the Terraba name. 

Euphorbia cyathophora Murray, Comm. Getting. 
7: 81. 1786. Poinsettia cyathophora (Murray) 
Klotzsch & Garcke, Monatsber. Konigl. Preuss. 
Akad. Wiss. Berlin 1859: 253. 1859. E. heter- 
ophylla var. cyathophora (Murray) Boiss. in DC., 
Prodr. 15(2): 72. 1862. 

Herbs, annual or perennial, stems erect or spreading 
to 0.5(-1 .5) m high, green and somewhat glaucous. Leaves 
at first alternate but becoming opposite distally, petioles 
5-15 mm long; leaf blades 5-10 cm long, 1-3 cm wide, 
pandurate to ovate, lanceolate or sublinear, apex acute, 
margin entire or with large teeth, base gradually nar- 
rowed to the petiole, glabrous or with short (0.3 mm) 
hairs, 2 veins 6-10/side. Inflorescences usually termi- 
nal, 1-2 cm long, to 3 cm wide, cymose and congested 
or of solitary cyathia, closely subtended by leaves usually 
reddish near the base or throughout, cyathia on pedun- 
cles ca. 3 mm long. Cyathia 2-3 mm long, narrowly 
campanulate, externally glabrous or short-puberulent, the 
solitary gland transversely oblong (elliptic-oblong) ca. 
1.4 mm wide and strongly bilabiate. Fruits ca. 4 x 5 
mm; seeds to 3 mm long, ellipsoid and truncated at the 
base, rounded or slightly angular in cross-section, surface 
tuberculate. 

Weedy plants of open sunny sites, 0-1000 m 
elevation. Rarely collected in Costa Rica (Meseta 
Central: Grayum 3921 MO, flowering and fruiting 
in August). The species ranges from the southern 
United States to northern South America. 

Euphorbia cyathophora is recognized by its her- 
baceous habit, alternate leaves on lower stems, 
small congested inflorescences closely subtended 
by foliage leaves marked with red and the solitary 
oblong glands. This species is closely related to E. 



116 



FIELDIANA: BOTANY 



heterophylla; both species are members of sub- 
genus Poinsettia and are currently being studied 
by M. May field (TEX). 

Euphorbia dwyeri Burch, Ann. Missouri Bot. Gard. 
54: 182, f. 1. 1967. 

Herbs or subshrubs 0.5-1.5 m tall, leafy stems 0.7-5 
mm thick, glabrous, terete; stipules reduced or repre- 
sented by a small prominence 0.4 mm wide. Leaves 
alternate on lower stems and often opposite at distal 
nodes, petioles 14-40(-60) mm long, 0.2-0.9 mm wide, 
glabrous; leaf blades 2-6 cm long, 1-3.5 cm wide, ovate- 
elliptic to ovate-lanceolate or ovate-suborbicular, apex 
bluntly acute or obtuse, base obtuse to rounded, drying 
membranaceous or thinly chartaceous, dark greenish 
above, glabrous or with few minute (0.2 mm) hairs in 
early stages, 2 veins 6-10/side. Inflorescences terminal 
or pseudoaxillary, 1-2.5 cm long, of 1-7 cyathia in cymes, 
glabrous except for narrow bracts with puberulent whit- 
ish apices, to 1 mm long, caducous, peduncles of the 
cyathia to 5 mm long. Cyathia ca. 2.5 mm long, 2-4 mm 
wide, glabrous in the lower half but with a distal rim of 
minute whitish hairs, glands 4, 0.7-2 mm wide; ovary 
borne on stipes becoming 5 mm long. Fruits 4-4.5 mm 
long, 4-6 mm wide, oblong-rounded, glabrous, smooth, 
columella ca. 4 mm long; seeds 2.5-3 mm long, ca. 2 
mm diam., ovoid-oblong, smooth, caruncle not devel- 
oped. 

Plants of montane forest formations, 1600-1800 
m elevation. Flowering in December-January; 
fruiting in January and March. This species is 
known only from Cerro Horqueta, Chiriqui, Pan- 
ama. 

Euphorbia dwyeri is recognized by its short weak- 
stemmed habit, restricted montane habitat, small 
thin rounded leaves, and small cyathia with four 
glands. The plants resemble E. segoviensis. 

Euphorbia elata Brandeg., Univ. Calif. Publ. Bot. 
6: 55. 1914. E. valerii Standl., J. Wash. Acad. 
Sci. 17: 11. 1927. 

Few-branched shrubs or treelets 1-5 m tall, leafy stems 
4-10 mm thick, glabrous; stipules 2-4 mm long, 1-3 
mm wide, at first deltoid, becoming thick and rounded. 
Leaves alternate, petioles 1 .5-7 cm long, 1 .2-5 mm wide, 
with lateral adaxial margins, glabrous; leaf blades 1 6- 
48 cm long, 5-13 cm wide, narrowly oblanceolate to 
narrowly obovate-oblong or linear-oblanceolate, apex 
bluntly acute to obtuse and slightly emarginate with gland 
tip, margin entire (sometimes undulate in life), base cu- 
neate and decurrent on the petiole, drying stiffly char- 
taceous to subcoriaceous, pale yellowish green beneath 
in life, 2 veins thin and obscure, 1 5-30/side, arising at 
right angles from the midvein. Inflorescences terminal, 
solitary, 14-50 cm long, open-cymose with few (2-6) 
dichotomous nodes, glabrous, peduncles 8-32 cm long, 
3-7 cm thick, primary branches 2-15 cm long, distal 
bracts 5-6 mm long, 2-3 mm broad at the base or the 



distal cyathia at first enclosed in opposite caducous ob- 
ovate-spatulate imbricate bracts 8-9 mm long, 5-6 mm 
wide, deciduous. Cyathia 8-10 mm long, 5-8 mm wide 
at apex, campanulate with a narrowed base, reddish, 
externally glabrous, with 5 distal perianth-like lobes 1 .5- 
3 mm long, with rounded usually sessile-appressed glands 
2-3 mm diam., internal bracts erose to fimbriate distally; 
anthers ca. 1.5 mm long, 0.5 mm wide; style column 2- 
3.5 mm long, style branches 2 mm long. Fruits 9-12 mm 
long, 1 1-14 mm wide, oblong, 3-lobed in cross-section, 
smooth, borne on a short (1-2 mm) stipe, columella 8- 
10 mm long; seeds 5-6.7 mm long, 4.5-6 mm diam., 
becoming invaginated when dried. 

Plants of evergreen forest formations, 10-1500 
m elevation. In Costa Rica, the species ranges along 
the Pacific slope from the northwestern volcanoes 
to the Osa Peninsula. (Rarely collected on the Ca- 
ribbean slope and with differing morphology; see 
below.) Probably flowering and fruiting through- 
out the year. The species ranges from Veracruz, 
Mexico, to the Amazon basin. 

Euphorbia elata is recognized by its woody few- 
branched habit, very long narrowly oblanceolate 
and entire leaves, long terminal inflorescences with 
opposite branching, and reddish cyathia with 
rounded flat appressed glands. As in other plants 
with very long narrow leaves, the main stems have 
few or no lateral branches. Three collections from 
the Caribbean slope (280-600 m elevation) are 
unusual in having emarginate leaf apices, longer 
inflorescences, shorter floral bracts (4-5 mm), and 
unisexual cyathia (Herrera 2266 and Schatz & 
Grayum 719 & 720; the latter two were described 
as dioecious). The relationships of this species are 
discussed in Webster and Huft (1988, p. 1 138). 

Euphorbia graminea Jacq., Sel. Stirp. Amer. 151. 
1763, and Obs. Bot. 2: 5, pi. 31. 1767. E. picta 
Jacq., Coll. 3: 178. 1790. Adenopetalum boer- 
haaviifolium Klotzsch & Garcke, Monatsber. 
Konigl. Preuss. Akad. Wiss. Berlin 1860: 47. 
1860. A. discolor KJotzsch & Garcke, loc. cit. 
49. 1860. A. hoffmanni Klotzsch & Garcke, loc. 
cit. 47. 1860. A. irasuense Klotzsch & Garcke, 
loc. cit. 50. 1860. A. pubescens Klotzsch & 
Garcke, loc. cit. 49. 1860. A. subsinuatum 
Klotzsch & Garcke, loc. cit. 48. 1860. E. gra- 
minea var. subsinuata (Klotzsch & Garcke) 
Boiss. in DC., Prodr. 15, 2: 54. 1862. Figure 29. 

Herbs 0.3-1.2 m tall, erect or decumbent, often with 
many distal branches, leafy nodes 0.5-4 mm thick, in- 
ternodes 2-10 cm long, glabrous or sparsely puberulent 
with thin whitish hairs 0.1-0.2 mm long; stipules re- 
duced or gland-like. Leaves alternate at lower nodes and 
opposite at distal nodes, petioles 5-50 mm long, 0.4-1 .4 



BURGER & HUFT: FLORA COSTARICENSIS 



117 



mm thick, glabrous or with few thin hairs, sulcate above; 
leaf blades (1.5-)2-7 cm long, (0.8-)l-5 cm wide, broad- 
ly ovate, ovate-elliptic to ovate-triangular or narrowly 
elliptic-oblong at distal nodes (rarely linear in southern 
Central America), apex acute to obtuse, margin entire, 
base broadly obtuse to truncate in larger leaves and acute 
in distal leaves, drying membranaceous or thinly char- 
taceous, grayish green, glabrous or with few to many thin 
hairs 0.1-0.4 mm long, 2 veins 4-8/side. Inflorescences 
terminal or pseudoaxillary, 0.5-15 cm long with di- 
chotomous branching, with 1-7 (15) flowers in open 
cymes, glabrous, peduncles 6-80 mm long, distal nodes 
subtended by spatulate bracts or reduced leaves 0.5-8 
mm long. Cyathia 1-3 mm long, campanulate cup ca. 
1-2 mm long, glands 2-4, petaloid appendages to 0.8 
mm long, 0.5 mm wide; ovary borne on a stipe ca. 1 
mm long (to 2 mm in fruit), ovary 0.7-1.3 mm long, 
glabrous, style branches 0.5-0.8 mm long, deeply bifid. 
Fruits 2-2.5 mm long, 2.5-3.5 mm wide, the 3 lobes 
rounded or angular in cross-section, columella 1 .4-2 mm 
long; seeds 1.5-2 mm long, 1-1.4 mm diam., surface 
with large (0.2-0.4 mm) angular pits forming a reticulum 
of irregular rows, brown to gray. 

Weedy plants of open sunny sites in evergreen 
to deciduous formations, 5-1600 m elevation. 
Probably flowering and fruiting throughout the year 
in evergreen areas. This species ranges from south- 
ern Mexico to coastal Peru. 

Euphorbia graminea is recognized by its her- 
baceous habit with many distal branches, longer 
internodes, larger alternate proximal leaves, smaller 
narrower distal leaves, and distinctly pitted seeds. 
The leaves near the inflorescences are often much 
narrower than those below. These plants are very 
variable in all parts of their range, appearing to 
belong to a single polymorphic species. (Klotzsch 
and Garcke synonyms cited above follow Stan- 
dley, 1937; they were based on Costa Rican col- 
lections but we have not seen the types.) See the 
discussion by McVaugh in Contr. Univ. Michigan 
Herb. 19: 220-227, 1993. 

Euphorbia heterophylla L., Sp. PI. 453. 1753. 
Poinsettia heterophylla (L.) Klotzsch & Garcke, 
Monatsber. Konigl. Preuss. Akad. Wiss. Berlin 
253. 1859. E. geniculata Ortega, Hort. Mat. Dec. 
1 8, 1 797. E. morisoniana Klotzsch in Seemann, 
Bot. voy. Herald 100. 1853. Figure 29. 

Erect herbs to 0.7(-1) m high, with a central taproot, 
stems usually with few distal branches, leafy stems 1.5- 
4 mm thick, glabrous or with few multicellular hairs 0.3- 
1.5 mm long near the nodes; stipules 0.3 x 0.5 mm, 
obscure. Leaves very variable in form on different plants, 
alternate but opposite below the inflorescences, petioles 
6-33(-55) mm long, 0.8-1.5 mm thick, glabrous or with 
few multicellular hairs, sulcate above; leaf blades 2-1 1 
cm long, 1.4-7 cm wide, ovate-elliptic to obovate or 
narrowly elliptic (rarely linear), often panduriform with 



2 broad lobes on the lateral sides separated by rounded 
sinuses, apex acute, the distal lobes more obtuse than 
the proximal, margins entire or dentate, base cuneate 
and decurrent on the petiole, drying membranaceous to 
chartaceous, glabrous or with simple hairs to 1 mm long, 
with minute scabrous hairs along the edge, 2 veins 6- 
12/side. Inflorescences terminal, 1-2 cm long, to 3 cm 
wide, closely subtended by leaves (sometimes with basal 
whitish markings), cymes fasciculate and crowded, pe- 
duncles of the cyathia to 6 mm long, yellowish. Cyathia 
with narrowly campanulate cup 2.5-3 mm long, ca. 2 
mm diam., glabrous externally, gland solitary (2), stalked 
with rounded apex ca. 0.8 mm diam.; anthers ca. 0.7 
mm wide; ovary ca. 2 x 2 mm, stipitate, styles ca. 1.3 
mm long. Fruits 3.5-4 mm long, 4-6 mm wide, 3-lobed, 
smooth, glabrous, columella 2.8-3 mm long; seeds 2.5- 
2.9 mm long, 1.9-2.2 mm diam., ovoid-oblong with 
truncated base and narrowed apex, surface minutely ir- 
regularly tuberculate. 

Common weedy plants of open sunny sites in 
both evergreen and deciduous areas (but rarely 
collected in Guanacaste), 0-2000 m elevation (to 
3000 m in the Andes). Flowering and fruiting 
throughout the year but restricted to the wet season 
in deciduous areas. The species ranges from Ari- 
zona, Mexico, and the West Indies to Peru. 

Euphorbia heterophylla is recognized by the erect 
herbaceous habit, alternate leaves on proximal 
stems, and small inflorescences closely subtended 
by opposite leaves that usually have white mark- 
ings at their base. The leaves are very variable in 
form on different plants. Panduriform leaves with 
two major lobes on each side separated by a round- 
ed sinus are distinctive, but they may be absent 
in many collections. This species is closely related 
to E. cyathophora\ both are part of subgenus Poin- 
settia, currently being studied by M. Mayfield (TEX). 

Euphorbia hoffmanniana (Klotzsch & Garcke) 
Boiss. in DC., Prodr. 15 (2): 99. 1862. Euphor- 
biastrum hoffmannianum Klotzsch & Garcke, 
Monatsb. Deutsch. Akad. Wiss. Berl. 252. 1859. 
Figure 30. 

Shrubs or small trees l-3(-5) m tall, leafy stems l-4(- 
6) mm thick, glabrous or with few thin hairs, terete; 
stipules reduced to short (0.2 mm) ridges 0.3-0.7 mm 
wide. Leaves alternate, petioles 6^40 mm long, 0.3-1.3 
mm wide, with thin lateral margins or slightly sulcate, 
glabrous; leaf blades 2-7 cm long, 0.8-3.5 cm wide, ovate- 
elliptic to ovate or elliptic (obovate), bluntly acute or 
obtuse at the apex, margin entire, obtuse to cuneate at 
the base and decurrent on the petiole, drying membra- 
naceous or thinly chartaceous and yellowish, glabrous, 
2 veins 8-14/side, loop-connected near the margin but 
often obscure. Inflorescences of solitary axillary flower- 
like cyathia, 4-10 mm long (rarely with ca. 3 cyathia on 
leafless axillary stems to 25 mm long), sometimes ter- 
minal and racemose by loss of distal leaves on stems to 



118 



FIELDIANA: BOTANY 



25 cm long, peduncles 1.5-5 mm long with 1-3 alternate 
bracts 1-2 mm long, cyathium enclosed by a condensed 
spiral of appressed imbricate obovate bracts 2-3 mm 
long, to 2 mm wide, apex broadly rounded or truncated. 
Cyathia with obconic involucre ca. 2 mm long, often 
hidden within the bracts, glands 5, 0.7-1.2 mm wide, 
yellow-green to orange in life, petaloid appendages ab- 
sent; anthers ca. 0.3 mm long, 0.4 mm wide; ovary ca. 
1 mm long, styles 0.5-0.7 mm long, bifid at the tips. 
Fruits ca. 4 x 5 mm, surfaces smooth and glabrous; 
seeds 2.2-2.5 mm long, 1.7-1.8 mm diam., rounded- 
oblong, with minute tubercles in longitudinal rows or 
scattered, grayish. 

Plants of partly deciduous and evergreen forest 
formations, 1 100-1 900(-2300?) m elevation. 
Flowering in January-March; fruiting in March- 
June. The species is endemic to Costa Rica and 
only known from the Pacific slope of the Cordillera 
de Tilaran (below Monteverde), the Meseta Cen- 
tral, and near Cartago-Paraiso. 

Euphorbia hoffmanniana is recognized by its 
inflorescences of solitary axillary flower-like cy- 
athia (appearing racemose when the leaves are de- 
ciduous) and the thin-walled involucre enclosed 
by imbricate bracteoles. The plants are glabrous, 
and the small alternate thin deciduous leaves are 
often absent when the plant is in flower. While 
this species is a small tree in seasonally dry areas, 
it is often found as a shrub in hedgerows at higher 
elevations. It is called lechilla. 



Euphorbia leucocephala Lotsy, Bot. Gaz. 20: 350, 
pi. 24. 1895. Figure 30. 

Shrubs or small treelets 1-5 m tall, crown usually 
much branched and rounded, leafy stems 0.8-4 mm thick, 
sparsely puberulent with thin hairs 0.2-0.4 mm long at 
the nodes, internodes glabrescent, terete, nodes thick- 
ened; stipules 0.3-0.7 mm long or not apparent, becom- 
ing gland-like. Leaves 2, 4, or 6 at each node, petioles 
6-24(-38) mm long, 0.2-0.7 mm thick, sparsely puber- 
ulent near base and apex; leaf blades 2.7-5(-6) cm long, 
0.7-2(-3) cm wide, elliptic-oblong to oblong or narrowly 
oblong, apex bluntly obtuse to rounded, slightly emar- 
ginate with a small (0.2-0.4 mm) mucronate tip, margin 
entire, base obtuse, drying thinly to stiffly chartaceous, 
pale grayish green or with reddish markings, glabrous 
above, with few to many thin white hairs beneath, 2 
veins 1 1-14/side, weakly loop-connected near the mar- 
gin. Inflorescences terminal or axillary to distal leaves, 
2-10 cm long, cymose-paniculate with opposing branch- 
es, major nodes subtended by small leaves or leaf-like 
bracts ca. 10 x 3 mm, distal flowers subtended by pet- 
iolate obovate-spatulate bracts 6-1 1 mm long, white and 
conspicuous in life. Cyathia 3-4 mm long, campanulate, 
borne on peduncles 1-2 mm long, with lobes ca. 1 .5 mm 
long, puberulent externally beneath the glands, the tri- 
angular petaloid appendages 1-3 mm long, 0.5-1 mm 
wide at the base. Fruits 5-6 mm long, 4.5-5.5 mm diam., 



subglobose and shallowly 3-lobed; seeds apparently not 
produced in Costa Rica and Panama. 

Euphorbia leucocephala is used extensively in 
Costa Rica as a garden ornamental. Its dense whit- 
ish crown and limited height make it an attractive 
little tree for gardens. The pale green leaves and 
many white bracts can make the entire crown ap- 
pear whitish. This species is called pascuite in 
Honduras, where it is used for making funeral 
wreaths. It grows naturally in deciduous wood- 
lands from Mexico to Nicaragua. 

Euphorbia neriifolia L., Sp. PI. 451. 1753. 

Shrubs 1-2 m tall, with cactus-like distal succulent 
green stems 8-30 mm thick, glabrous, usually with 3-5 
angles and often leafless, stipular spines 1-4 mm long, 
paired from a rounded base 2-5 mm, wide, dark. Leaves 
alternate, deciduous or caducous, petioles 5-20 mm long 
but poorly differentiated from the lamina, glabrous; leaf 
blades 6-20 cm long, 2-4.5 cm wide, linear-oblanceolate 
to narrowly obovate-oblong, apex rounded or bluntly 
obtuse, margin entire, base cuneate and long-attenuate, 
succulent in life, drying grayish green, glabrous, 2 veins 
usually obscure. Inflorescences axillary, ca. 10 mm long, 
sessile or subsessile with usually 3 cyathia, peduncles 0- 
6 mm long, to 1.5 mm thick, bracteoles ca. 4 mm long, 
to 5 mm wide, opposite and imbricate, at first enclosing 
the cyathium. Cyathia ca. 4 mm long, ca. 6 mm wide, 
glands 5, to 4 mm wide, lacking petaloid appendages, 
bracteoles of the $ cymules fimbriate distal ly. 

Euphorbia neriifolia is often planted in hedges 
and along walls in warmer dry climates. The thick 
cactus-like (usually leafless) spiny stems and short 
axillary inflorescences are distinctive. These plants 
are commonly planted in the Pacific lowlands of 
northern Central America, but we have not seen 
material from Costa Rica. Compare E. splendens. 

Euphorbia ocymoidea L. Sp. PI. 453. 1753. E. as- 
troites Fish. & Mey., Index Sem. Hort. Petrop. 
10:44. 1845. Figure 6. 

Herbs 1 5-60 cm tall, erect annuals, usually with many 
1 and 2 branches, leafy stems 0.2-1 mm thick, puber- 
ulent with minute (ca. 0.2 mm) simple and gland-tipped 
hairs, main stems usually glabrate; stipules not devel- 
oped. Leaves alternate, but usually opposite at distal 
nodes, petioles 1-16(-30) mm long, 0.1-0.3 mm wide, 
glabrous or sparsely and minutely puberulent; leaf blades 
4-1 5(-20) mm long, 4-1 3(-l 8) mm wide, broadly ovate- 
orbicular to ovate-rhombic or ovate-triangular, apex ob- 
tuse or rounded, margin entire, base truncate-rounded 
to broadly obtuse, drying membranaceous, with thin 
whitish hairs 0.2-0.4 mm long on both surfaces, 2 veins 
2-5/side, thin and often obscure. Inflorescences terminal 
or axillary at distal nodes, 2-3 mm long, of solitary cy- 
athia on peduncles 0.5-1.7 mm long, slender, Cyathia 



BURGER & HUFT: FLORA COSTARICENSIS 



119 



with involucres ca. 0.4 mm long, 0.3-0.4 mm wide, nar- 
rowly campanulate to obconic, green, with thin whitish 
hairs ca. 0.2 mm long externally, glands usually 4 (5), 
with 3- or 4-parted or dentate appendages, styles 0.3- 
0.4 mm long, bifid to base. Fruits ca. 1.5 mm long, 1.6- 
1.8 mm wide, with thin hairs to 0.3 mm long (rarely 
glabrous), borne on pedicels 1.4-2(-4) mm long, colu- 
mella 1-1.1 mm long; seeds 0.9-1.1 long, 0.7-0.8 mm 
diam., ovoid-ellipsoid, with deep pits in well-defined 
depressions ca. 0.2 mm wide and tuberculate on the rims 
between the depressions. 

Plants of seasonally dry deciduous or partly de- 
ciduous formations, 50-1 100 m elevation (to 1900 
m in Guatemala). Flowering in September-De- 
cember; fruiting in December-January. The spe- 
cies ranges from western Mexico along the Pacific 
slope to Panama. 

Euphorbia ocymoidea is recognized by its sea- 
sonal habitats, the slender herbaceous stems, lat- 
eral branches with gland-tipped hairs and small 
(ca. 5x5 mm) leaf blades, and unusual pitted- 
tuberculate seeds. Euphorbia astroites with glan- 
dular hairs and E. ocymoides with eglandular hairs 
are now interpreted to be the same species, with 
material from southern Central America often 
having glandular hairs. 

Euphorbia oerstediana (Klotzsch & Garcke) Boiss. 
in DC., Prodr. 15 (2): 59. 1862. Poinsettia oer- 
stedianum Klotzsch & Garcke, Monatsber. 
Konigl. Preuss. Akad. Wiss. Berlin 253. 1859. 
Figure 29. 

Herbs to 1.5 m tall, erect and usually branched from 
the base with few distal branches, stems not completely 
articulate, glabrous or with thin hairs to 1 mm long; 
stipules not developed. Leaves alternate or opposite at 
distal nodes, petiole 5-20 mm long, glabrous; leaf blades 
2-8 cm long, 1-3.6 cm wide, broadly ovate to ovate- 
lanceolate or oblong, apex acute to obtuse, margin entire, 
base obtuse to rounded, drying membranaceous or thinly 
chartaceous, glabrous or puberulent beneath, 2 veins 6- 
9/side. Inflorescences terminal, 1-3 cm long, cymose 
with dichotomous branching, glabrous or puberulent, 
bracts ca. 1 mm long, narrow, peduncles of cyathia 1.5- 
6 mm long. Cyathia 2-2.5 mm long, 0.8-1.5 mm diam., 
with usually 2 large (ca. 1.3 x 0.8 mm) distal rounded 
lobes (= glands?), 1-3 smaller also often present; ovary 
covered with a minute pale grayish puberulence. Fruits 
ca. 4 mm long, 34 mm wide, ovoid, surface minutely 
puberulent; seeds 2.5-2.9 mm long, 1.7-2 mm wide, 
surface with distinctive rounded papilla-like projections 
0.2-0.3 mm diam., minutely carunculate, grayish. 

Weedy plants of open sunny sites, 0-1500 m 
elevation (to 2500 m in Guatemala). Probably 
flowering primarily in the wet season (June-No- 
vember). This species is rarely collected in south- 



ern Central America. The species ranges from 
Mexico and the West Indies to northern South 
America. 

Euphorbia oerstediana is recognized by its her- 
baceous habit, ovate-lanceolate leaves, small in- 
florescences, and seeds covered with unusual pa- 
pillae. 

Euphorbia peplus L., Sp. PI. 456. 1753. 

Herbs 10-40 cm tall, leafy stems 0.3-3(-4) mm thick, 
glabrous, terete, green; stipules absent. Leaves alternate 
near the base, 2-3 at distal nodes, sessile or with slender 
petioles to 5 mm long; leaf blades 6-25 mm long, 4-15 
mm wide, broadly elliptic to rounded-ovate or obovate, 
apex rounded to obtuse, margin entire, base acute to 
cuneate or broadly obtuse (subtruncate), bright green in 
life, drying membranaceous, glabrous, 2 veins 2-4/side, 
strongly ascending. Inflorescences terminal or axillary, 
umbellate, of solitary cyathia subtended by foliage leaves 
slightly smaller (4-8 mm) than those of distal stems, 
peduncles 0.6-1 mm long, glabrous. Cyathia with in- 
volucre 0.8-1.1 mm long, 0.5-1 mm wide at apex, ob- 
conic, glabrous externally, glands 4, crescent-shaped and 
with prolonged linear lobes 0.5-0.7 mm long (petaloid 
appendages absent). Fruits 1.8-2.2 mm long, 2.2-2.5 
mm wide, ovoid-oblong, smooth and glabrous, borne on 
pedicels 1.3-3 mm long, columella 1.3-1.4 mm long; 
seeds 1-1.5 mm long, 0.8-1 mm wide, oblong with a 
prominent caruncle, pale grayish with pronounced ob- 
long depressions 0.5-0.7 mm long on the adaxial sur- 
faces, with rounded dark depressions in longitudinal rows 
of 3-4 on the abaxial surfaces. 

Euphorbia peplus is originally from Eurasia but 
has now become a weed in many moist temperate 
and tropical montane habitats. In Central Amer- 
ica, it is known only from elevations of 1 500-2500 
m in Guatemala and Chiriqui, Panama. The small 
stature and many thin rounded leaves in dense 
leafy, closely clustered, distal branchlets give the 
living plants a distinctive appearance. 

Euphorbia pulcherrima Willd. ex Klotzsch, Allg. 
Gartenz. 2: 27. 1834. Poinsettia pulcherrima 
Graham, Edinb. New Phil. J. 20: 421. 1836. E. 
erithrophylla Bertol., Fl. Guat. 419. 1840. 

Shrubs or small treelets 0.5-3(-5) m tall, erect, usually 
with few lateral branches, leafy stems 3-9 mm thick, 
glabrous, terete; stipules represented by gland-like ridges 
ca. 1.5 mm wide. Leaves alternate (opposite or whorled 
beneath the inflorescence), petioles 2-8 cm long, 0.8-2 
mm thick, glabrous or very sparsely puberulent, narrow- 
ly sulcate above; leaf blades 8-22 cm long, 4-1 2 cm wide, 
narrower (1-2 cm wide) beneath the inflorescences, el- 
liptic to ovate-oblong or pandurate (with 2 prominent 
tooth-like lobes separated by a rounded sinus on each 
side), apex acute, margins entire, base obtuse to acute, 
with thin crooked hairs ca. 0.4 mm long, 2 veins 8-1 5/ 



120 



FIELDIANA: BOTANY 



side. Inflorescences terminal or leaf-opposed, cymose- 
corymbose, subtended by brilliant red (pink, white) ob- 
lanceolate leaves. Cyathia 6-7 mm long, urceolate, gla- 
brous externally, distal margin fimbriate, gland solitary, 
4-5 mm wide, transversely oblong, yellow. 

Euphorbia pulcherrima is widely used as an or- 
namental shrub in parks and gardens. Its flowering 
time (November-December) and strongly con- 
trasting bracts (brilliant red) and foliage (deep green) 
have made it a Christmastime favorite (flor de 
pascua, pastora, "poinsettia"). It is thought to be 
native to southern Mexico and northern Guate- 
mala; see Standley and Steyermark (1949, pp. 111- 
1 1 2). It is not known to grow wild in southern 
Central America. 

Euphorbia sen lech tendalii Boiss., Cent. Euphorb. 
18. 1860. E.friedrichsthalii Boiss. in DC., Prodr. 
15 (2): 61. 1862. E. adinophylla J. D. Smith, 
Bot. Gaz. 47: 261. 1909. Figure 30. 

Shrubs or small trees 0.5-5 m tall, trunks to 20 cm 
diam. at the base, older stems with thin peeling bark, 
leafy stems 0.4-5 mm thick, often reddish, glabrous or 
with few minute (0.1 mm) whitish hairs at the nodes, 
nodes slightly thickened; stipules ca. 0.3 mm long, ob- 
scure, becoming gland-like. Leaves opposite or verticil- 
late with 4, 6, or 8 leaves/node, petioles 5-35 mm long, 
0.2-0.6 mm thick, glabrous or minutely (0.05 mm) pu- 
berulent at the base; leaf blades 13-40 mm long, 8-18 
mm wide, ovate-elliptic to ovate-suborbicular or elliptic, 
apex rounded to bluntly obtuse or bluntly acute, margin 
entire, base cuneate to obtuse, drying membranaceous 
or thin-chartaceous, glabrous above and below, 2 veins 
3-8/side. Inflorescences terminal or axillary to distal 
nodes, 1-2 cm long, cymose and often hemispheric with 
2-8 cyathia/node, peduncles 2-6 mm long, bracts usually 
sessile and ca. 0.7 mm long or sometimes leaf-like and 
narrowly oblanceolate to 4 mm long, 0.8-2 mm wide, 
glabrous, yellowish. Cyathia 2-3 mm long, 3-4 mm wide 
at the apex, campanulate, glabrous externally; glands 5, 
1-2 mm wide; filaments ca. 1.2 mm long, anthers ca. 
0.3 mm long, 0.5-0.7 mm wide, thecae subglobose; ova- 
ry ca. 1.5 x 1.5 mm, borne on a stipe 1-4 mm long, 
styles united at the base, 1-2 mm long, bifid for most of 
their length. Fruits 4-5 mm long, 5-7 mm wide, con- 
spicuously 3-lobed, surfaces smooth, columel la ca. 3 mm 
long; mature seeds not seen, apparently 3 mm long and 
with a wrinkled surface. 

Plants of seasonally deciduous forest forma- 
tions, 1 0-1 300 m elevation (to 1 500 m in Mexico). 
Flowering in November-April, often when leaf- 
less. The species ranges from northeastern Mexico 
to Guatemala and along the Pacific slope to north- 
ern Costa Rica. 

Euphorbia schlechtendalii is recognized by its 
woody habit, general lack of pubescence, verticil- 
late leaves with thin rounded blades on slender 



petioles, and small inflorescences often in bloom 
when the leaves have fallen. The stems are quite 
brittle and are easily broken at the nodes. The 
species has been used as the source of a purgative 
in Mexico. An unusual leafless collection, with 
condensed inflorescences and cyathia minutely 
puberulent on the exterior, from Sta. Rosa Na- 
tional Park is tentatively placed here ( Wilbur 25084 
DUKE). 

Euphorbia segoviensis (Klotz. & Garcke) Boiss. in 
DC, Prodr. 15 (2): 58. 1862. Leptopus sego- 
viensis Klotz. & Garcke, Abh. Konigl. Akad. 
Wiss. Berlin 46. 1859. E. chiapensis Brandegee, 
Univ. Calif. Publ. Bot. 6: 54. 1914. Figure 29. 

Herbaceous subshrubs 1-2 m tall, leafy stems 0.4-3.5 
mm thick, terete, glabrous or with thin curved hairs ca. 
0.5 mm long; stipules minute or absent. Leaves alternate 
(opposite or ternate at branching nodes), petioles 5-35 
mm long, 0.2-0.4 mm wide, glabrous; leaf blades 1.5- 
4(-6) cm long, l-2(-3) mm wide, ovate-elliptic to nar- 
rowly ovate-oblong or oblong, apex bluntly obtuse to 
rounded, minutely mucronate, margin entire, base ob- 
tuse, drying membranaceous, venation pinnate, 2 veins 
4-7/side, central 2 veins arising at angles of 70-90. 
Inflorescences terminal or axillary, slender leafy cymes, 
often umbellate at ends of branchlets, glabrous or mi- 
nutely puberulent with short (0.4 mm) thin hairs. Cy- 
athia with involucre 1-1.5 mm long, minutely puberu- 
lent with thin hairs, glands 5, transversely oblong, with 
2 linear or narrowly oblong lobes 0.5-0.8 mm long, ca. 
0.2 mm wide; styles bifid. Fruits ca. 2.5 mm diameter, 
glabrous; seeds ca. 1 .4 mm long, with conspicuous pits, 
gray. 

Rarely collected plants of partly deciduous and 
evergreen forest formations, 400-1200 m eleva- 
tion. The species ranges from central Mexico to 
the Meseta Central of Costa Rica. 

Euphorbia segoviensis is recognized by its slen- 
der herbaceous habit, thin leaves on long slender 
petioles, and 10 narrow corolla-like lobes (two per 
gland) on the margin of the cyathium. The name 
is based on an Oersted collection from Nicaragua. 
We thank V. W. Steinman, a student at RSA, for 
suggesting the use of this name in place of E. chia- 
pensis; he also points out that it is very unlikely 
that E. chiapensis is a synonym of E. zierioides 
Boiss. (cf. Croizat in J. Arnold Arb. 26: 1 94, 1 945). 

Euphorbia splendens Hook., Bot. Mag. pi. 2902. 
1 829. E. milii Des Moul. var. splendens (Hook.) 
Ursch & Leandri, Mem. Inst. Scient. Madagas- 
car, sen B, 5: 144. 1955. 

Scandent shrubs or subshrubs with woody stems to 
1.5 m long, few-branched, stems 4-12 mm thick, gla- 



BURGER & HUFT: FLORA COSTARICENSIS 



121 



brous, with sharp paired straight stipular spines 4-18 
mm long, ca. 1 mm thick near the base, grayish, sepa- 
rated by short (3-5 mm) internodes. Leaves alternate, 
present only at the distal nodes, petioles not differenti- 
ated from the cuneate lamina base; leaf blades 1 .3-1 (-12) 
cm long, 0.6-2(-4) cm wide, narrowly obovate to oblong- 
spatulate or elliptic, apex with a short (0.7 mm) slender 
tip, margin entire, base cuneate and long-decurrent, gla- 
brous. Inflorescences axillary to distal leaves, 5-14 cm 
long, with few distant dichotomies, peduncles to 7 cm 
long, 1-2 mm thick, glabrous, cyathia borne on pedun- 
cles ca. 6 mm long. Cyathia subtended and closely en- 
veloped by 2 opposite petaloid bracteoles 8-12 mm long, 
bracteoles expanded distally and broadly rounded, 6-12 
mm wide, red, pink, or yellowish, the cyathium with 5 
glands around the periphery of cup. 

Euphorbia splendens (also called E. milii) is a 
popular ornamental species recognized by its many 
close sharp straight spines, few distal leaves, open 
dichotomous inflorescences and "flowers" (cy- 
athia) with two large rounded colorful "petals" 
(appressed bracts). The spiny scandent stems make 
this a favorite cultivar for garden walls and edg- 
ings. The species originated in Madagascar and is 
now cultivated throughout the tropics and sub- 
tropics. We follow Carter (Ann. Missouri Bot. 
Gard. 81: 368, 1994) in using the widely known 
name. It is called corna de Cristo and "crown of 
thorns." 

Euphorbia tirucalli L., Sp. PI. 452. 1753. 

Shrubs or small trees 1.5-10 m tall, dioecious, trunks 
to 1 5 cm thick, crown with many erect branches, branch- 
lets 1.5-4 mm diam., green, striate on drying, lenticel- 
late. Leaves usually absent, alternate and quickly cadu- 
cous, less than 2 cm long, the smaller and larger branches 
photosynthetic. Inflorescences terminal or axillary to 
distal leafless nodes, 5-15 mm long, to 15 mm wide, 
sessile dense fascicles with short (1-2 mm) scarious bracts 
and subsessile crowed cyathia. Cyathia ca. 2 x 1.5 mm, 
obconic, minutely puberulent externally, with perianth- 
like distal lobes, glands 5, 1-1.5 mm wide; ovary 2.5-3 
mm long, 1.5-2 mm diam., densely puberulent exter- 
nally, becoming exserted on a thick (0.7 mm) stipe to 4 
mm long, style branches less than 1 mm long, recurved. 

Euphorbia tirucalli is often planted in parks and 
at the edges of gardens; it is sometimes used in 
hedgerows. The dense crown of many cylindrical 
(mostly vertical) green branches and leafless 
branchlets gives it an unusual appearance. Com- 
mon names are pizarrin and "Indian finger tree." 
The species is probably native to eastern Africa 
and India. 

Euphorbia xalapensis H.B.K., Nov. gen. sp. 2:61. 
1817. Poinsettia xalapensis (H.B.K.) Klotzsch 



& Garcke, Monatsber. Konigl. Preuss. Akad. 
Wiss. Berlin 1859: 253. 1859. E. enalla Bran- 
deg., Univ. Calif. Publ. Bot. 6: 54. 1914. E. 
amphilmalaca Standl., Publ. Field Columb. 
Mus., Bot. Ser. 4: 313. 1929. Figure 29. 

Herbs 20-60(-100) cm high, erect or sprawling, leafy 
stems 0.4-2.5 mm thick, puberulent with thin multicel- 
lular hairs 0.4-1 mm long, internodes 2-10 cm long; 
stipules 0.1-0.2 mm wide, gland-like. Leaves alternate 
at lower nodes and 3/node distally, petioles 5^45 mm 
long, 0.3-1 mm thick, flattened above, puberulent, often 
variable in length on the same stem; leaf blades 1 .5-6(-9) 
cm long, l-3(-3.8) cm wide, ovate-elliptic to broadly 
ovate or narrowly elliptic-oblong, apex acute or obtuse, 
margin entire, base obtuse to truncate and rounded, dry- 
ing grayish green and paler beneath, with crooked mul- 
ticellular hairs 0.5-1.3 mm long above, more densely 
pubescent beneath, 2 veins 3-6/side. Inflorescences ter- 
minal, often paired (lateral to an undeveloped apex), 3- 
12 mm long, with 1-5 cyathia, becoming 1 -sided by 
abortion, subtended by reduced opposite narrow leaves 
ca. 7 mm long, peduncles 2-5 mm long. Cyathia 0.7- 
1.5 mm long, 0.5-1 .3 mm wide, obconic to campanulate, 
with conspicuous whitish hairs, glands 5, petaloid ap- 
pendages 0.2-2 mm long, 0.7-1.2 mm wide; ovary ca. 
1 mm long, styles 0.7-1 .2 mm long, free and deeply bifid, 
stipe becoming 1.3-2.8 mm long in fruit. Fruits 2-2.3 
mm long, 2.3-2.6 mm wide, sparsely and minutely pu- 
berulent, ovoid with rounded or truncate base, columella 
1-1.6 mm long; seeds 1.1-1.7 mm long, 0.8-1.2 mm 
diam., with deep angular pits 0.2-0.3 mm wide in lon- 
gitudinal ranks. 

Plants of open sites in deciduous or partly de- 
ciduous formations, (200-) 1 300-2 1 00 m eleva- 
tion. Probably flowering and fruiting primarily in 
the late wet season, November-December. Inter- 
estingly, nearly all the collections from Honduras 
and southern Central America come from between 
1700 and 2000 m elevation. The species ranges 
from western Mexico to Honduras, with a few 
collections from Costa Rica and western Panama. 

Euphorbia xalapensis is recognized by its short 
herbaceous habit with long internodes, multicel- 
lular hairs ( x 50), small inflorescences lacking col- 
orful bracts, five involucral glands, and seeds with 
conspicuous pits. Material of this species has often 
been mistakenly referred to the rarely collected E. 
oerstediana (q.v.). 



Garcia Vahl 

Shrubs or small trees, monoecious, hairs simple; stip- 
ules absent. Leaves alternate, simple, petioles thickened 
(geniculate) at base and apex, without glands, blades en- 
tire, pinnately veined. Inflorescences terminal, usually 
bisexual, apparently reduced cymes, with 1-2 9 flowers 



122 



FIELDIANA: BOTANY 



and several 6 flowers at a node, pedicels slender ($) or 
thick (2). Male flowers globose in bud, pubescent, calyx 
rupturing into 2-3 valvate parts, persisting, corolla of 6- 
1 3 petals longer than the sepals, disk intrastaminal and 
dissected; stamens 30-100 on a convex receptacle, fila- 
ments free; pistillode absent. Female flowers with calyx 
rupturing into 2-3 parts, caducous, corolla similar to <5, 
disk deeply lobed, staminodes absent; ovary 3-locular, 
ovules 1/locule, style column short, style branches thick, 
reflexed and bifid. Fruits capsular, breaking explosively 
into 3 2-valved cocci; seeds subglobose, ecarunculate, 
endosperm copious. 

A Neotropical genus of two species, G. nutans 
(see below) and G. parviflora Lundell of eastern 
Mexico. The geniculate petioles, relatively large 
flowers, many stamens, and large fruits help to 
distinguish this genus. Lundell has claimed that 
the genus is a potential source of superior quick- 
drying oil (see Wrightia 1: 1-12, 1945). 

Garcia nutans Vahl in Rohr, Skr. Naturhist. Selsk. 
Kjobenhaven 2: 217, t. 9. 1792. Figure 21. 

Shrubs or small trees 2-6 (9) m tall, trunks to 50 cm 
diam . . leafy stems 1 .5-4.5 mm thick, sparsely to densely 
hirtellous with yellowish hairs to 0.3 mm long, quickly 
glabrescent and becoming dark reddish brown. Leaves 
with petioles 1.6-6 cm long, 1-2.8 mm thick, with long 
(48 mm) thickened areas at both apex and base (drying 
dark), glabrescent; leaf blades 7-20 cm long, 2.5-9 cm 
wide, oblong to elliptic-oblong or oblong-obovate, apex 
caudate-acuminate with a tip 3-12 mm long, gradually 
narrowed to a cuneate or rounded base, margin entire 
and thickened, drying stiffly chartaceous to subcoria- 
ceous, with thin hairs or glabrescent beneath, 2 veins 
4-10/side. Inflorescences terminal, of 1-5 flowers on 1- 
3 peduncles, densely velutinous/sericeous, 9 pedicels to 
30 mm long, 0.8-2 mm thick (to 3 mm thick in fruit). 
Male flowers ca. 3 cm wide, sepals 5-8 mm long, 1.5- 
3 mm wide, densely yellowish pubescent on both sur- 
faces, petals usually 7-10, pink to purple, 4-12 mm long, 
1.5-3 mm wide, with thin whitish hairs 1-1.3 mm long, 
glabrous within near the base; stamens many from a 
pilose base, filaments 3-5 mm long, 0.1-0.2 mm wide, 
red, anthers 0.6-0.9 mm long, yellow. Female flowers 
with perianth similar to $ but caducous, the annular disk 
0.5-1 mm high, deeply lobed; ovary 3.5-4 mm long, 4- 
5 mm diam., stylar column 1.5-2 mm long, 1.3-2 mm 
thick, both ovary and style column densely velutinous, 
style branches 1.5 mm long, equally broad, red drying 
black, glabrous. Fruits 2-2.5 cm long, 3-4 cm broad, 
densely yellowish velutinous, wall of the cocci 0.8-1.5 
mm thick, columella 13-19 mm long, 10-13 mm broad 
distally, T-shaped; seeds 14-17 mm long, 12-15 mm 
wide, 12-14 mm thick, subglobose with a slight longi- 



tudinal ridge from apex to base, surface smooth and pale 
grayish brown. 

Plants of the understory in seasonally very dry 
or partly deciduous forests of northwestern Costa 
Rica, 1 0-200 m elevation (to 500 m in Nicaragua). 
Probably flowering in all months; fruiting in Oc- 
tober-May. The species ranges from central Mex- 
ico to northwestern Costa Rica, with a few collec- 
tions known from Panama and Colombia where 
the species may have been introduced. 

Garcia nutans is recognized by its deciduous 
forest habitat, the oblong leaves with distinctive 
petioles thickened at both apex and base, the few 
large terminal flowers with ca. 10 reddish petals, 
many stamens with red filaments, and larger fruit. 
The plants have been used medicinally in Colom- 
bia as a purgative, with a single seed said to be 
sufficient to induce vomiting. 



Gymnanthes Swart/ 

Shrubs or trees, monoecious (rarely dioecious), latex 
scant and not milky, glabrous or with simple hairs; stip- 
ules paired at the leaf base, stipule-like bud-scales some- 
times present. Leaves alternate, simple, lacking glands 
at the apex of the petioles, pinnately veined, margins 
glandular or eglandular and entire or crenulate, often 
coriaceous. Inflorescences axillary, bisexual (rarely uni- 
sexual), solitary, spiciform, with l(-few) proximal sessile 
to long-pedicellate 9 flowers and many distal cymules, 
bracts mostly biglandular, $ flowers pedicellate. Male 
flowers naked or with 1-2 rudimentary calyx lobes, petals 
and disk absent; stamens often 3 (2-6), filaments free or 
variously connate near base, anthers dehiscing longitu- 
dinally and extrorse; pistillode absent. Female flowers 
usually with 3 small sepals or naked (petals and disk 
absent); ovary sessile or stipitate, 3-locular, ovules 
1/locule; styles free or basal I \ connate, style branches 
simple. Fruits capsular, breaking into 3 2-valved cocci, 
the columella persistent; seeds subglobose, caruncule 
present, testa smooth, endosperm copious. 

A Neotropical genus with ca. 1 5 species, ranging 
from the southern United States and Mexico into 
Central America. The small flowers with nearly 
obsolete perianth are distinctive. One species is 
frequently collected in Costa Rica, but an addi- 
tional species is likely to be found in the Caribbean 
lowlands. Webster includes Actinostemon within 
Gymnanthes (Webster, 1994b). 



Key to the Species of Gymnanthes 

la. Ovary minutely puberulent, fruits puberulent to subglabrous; seeds 6-9 mm long; leaf blade 6-16 
cm long, chartaceous to subcoriaceous G. riparia 



BURGER & HUFT: FLORA COSTARICENSIS 



123 



1 b. Ovary and fruits glabrous; seeds ca. 5 mm long; leaf blades to 1 1 cm long, usually subcoriaceous 
[not known from southern Central America] G. lucida 



Gymnanthes lucida Sw., Prodr. 96. 1788. Ater- 
amnus lucidus (Sw.) Rothm., Feddes Repert. 53: 
5. 1944. Figure 26. 

Small to medium-sized trees 5-20 m tall, monoecious, 
leafy stems 1-4 mm thick, glabrous, drying grayish; stip- 
ules ca. 1 mm long, caducous, scars 0.3-0.7 mm wide. 
Leaves articulated at base, petioles 3-1 1 mm long, 0.6- 
1.2 mm thick, glabrous, slightly thickened or bent below 
the blade; leaf blades 2.5-1 1 cm long, 1-4 cm wide, 
narrowly obovate to oblanceolate-spatulate, narrowly el- 
liptic-oblong, bluntly acute to rounded at the apex, mar- 
gin subentire with minute (0.2 mm) gland-tipped teeth, 
base acute to cuneate and slightly rounded at the petiole, 
drying subcoriaceous and grayish green, glabrous above 
and below, often with dark glandular areas 0.4 mm diam. 
near the base, 2 veins 5-10/side, loop-connected near 
the margin, major and minor venation prominent above 
and below. Inflorescences axillary or terminal, bisexual 
or 9, usually cone-like in early stages (ca. 4x2 mm) and 
covered with spirals of appressed imbricate scales ca. 0.8 
mm wide, sessile or on a short (2 mm) peduncle, 7-28 
mm long and ca. 3 mm wide at anthesis, axis glabrous. 
Male flowers subtended by small (1 mm) bracts, borne 
on pedicels ca. 0.6 mm long, without a definite perianth; 
filaments partly united into a column, anthers 3-5, ca. 
0.4 mm long, oblong. Female flowers solitary from the 
base of the raceme or 1-2 in the axils of leaves, peduncles 
12-30 mm long (base-to-bracteoles), ca. 0.6 mm thick, 
glabrous, pedicel (stipe) 5-7 mm long, continuous with 
the base of the ovary, ovary ca. 3 x 2.7 mm, style column 
ca. 1 mm long, style branches 1.5 mm long, recurved. 
Fruits 7-8 mm long, 9-10 mm wide, oblate and 3-lobed, 
rounded, glabrous; seeds 4.5-5.2 mm long, 44.5 mm 
wide, 3.5-3.8 mm thick, smooth and rounded, dark 
brown, caruncle 1.5 mm wide, broadly rounded. 

Plants of evergreen or partly deciduous forest 
formations, 0400 m elevation. Probably flower- 
ing and fruiting in the wet season, May-Novem- 
ber. The species is found in the southern United 
States, Mexico, Belize, Guatemala, Cuba, and the 
Bahamas. 

Gymnanthes lucida is recognized by its lack of 
pubescence, small stiff often obovate leaves, cone- 
like inflorescence buds, glabrous naked 2 flowers, 
and solitary fruit. The hard heavy wood has 
strongly contrasting color in sapwood and heart- 
wood; it has been used for veneers and other uses. 
While not known from southern Central America, 
this species may be expected along the Caribbean. 

Gymnanthes riparia (Schldl.) Klotzch, Arch. Na- 
turgesch. 7: 1 82. 1 84 1 . Excoecaria riparia Schldl. 
Linnaea 7: 386. 1832. G. guatemalensis Standl. 
& Steyerm., Publ. Field Mus. Nat. Hist., Bot. 
Ser. 23: 122. 1944. Figures 12 and 26. 



Trees 4-20 m tall, trunks 10-49 cm diam., leafy stems 
1.5-5 mm thick, glabrous or with a few minute appressed 
hairs in early stages; stipules 0.7-1.8 mm long, 0.5-0.7 
mm broad at the base, triangular, minutely appressed- 
puberulent, caducous. Leaves with petioles 4-16 mm 
long, 1-2.7 mm thick, glabrous or with a few minute 
appressed hairs in early stages, glands absent; leaf blades 
6-16(-20) cm long, 2-6.5(-8) cm broad, obovate to el- 
liptic-obovate, oblong-obovate, or narrowly elliptic-ob- 
long, apex acute to caudate-acuminate with narrowed tip 
4-14 mm long, serrulate to subentire with 12-16 glands 
along the margin, base cuneate (obtuse) and slightly de- 
current on the petiole, drying stiffly chartaceous to sub- 
coriaceous, yellowish to grayish green, glabrous, 2 veins 
5-8(-l l)/side, distal veins loop-connected. Inflores- 
cences 1-3/axil, bisexual or unisexual, <3 to 5 cm long, 
spiciform with 1-3 flowers in glomerules 0.3-4 mm dis- 
tant along the slender (0.4 mm) puberulent rachis, bracts 
0.3-1 mm long, pedicels 1-2 mm long, puberulent; 9 
inflorescences ca. 2 cm long, to 4.5 cm in fruit, pedicels 
3-6 mm long, 0.4 mm thick. Male flowers usually of 3 
(2-5) stamens subtended by a small (0.3-0.5 mm) bract- 
like perianth part at the apex of the pedicel, filaments 
0.5-1.8 mm long, 0.1 mm thick, glabrous, anthers 0.2- 
0.3 mm long, 0.3-0.4 mm wide. Female flowers with 0- 
2 bract-like perianth parts (ca. 0.3 mm long) at the apex 
of the pedicel, ovary 1.5-2.3 mm long, 1.3-2 mm diam., 
ovoid, with dense minute (0.1 mm) velutinous hairs, 
style branches 3, 1 .5-3.5 mm long, 0.3 mm thick, smooth, 
persisting. Fruits 9-12 mm long, 13-16 mm broad, 
rounded-oblong, 3-lobed, greenish, minutely pubescent, 
cocci with outer walls 1-2 mm thick, columella 8-10 
mm long, 4-6 mm broad in the distal half; seeds 5-8 
mm long, 5-6 mm wide, 4.5-5.5 mm thick, rounded- 
oblong, caruncle slightly (0.5-1 mm) elevated. 

Plants of wet evergreen forests on the Caribbean 
slope, northernmost cloud forests, and Osa Pen- 
insula, (50-)200-1100 m elevation. Flowering in 
May-November; fruiting in July-December. The 
species ranges from Veracruz, Mexico, to southern 
Costa Rica. 

Gymnanthes riparia is recognized by the stiff 
glabrous leaves glandular along the edge, short 
slender inflorescences, naked flowers with minute 
vestigial perianth parts, rounded fruits with per- 
sisting stigmas, and thick-walled cocci. A collec- 
tion from Puerto Viejo de Limon (Hartshorn 1853) 
has smaller subglabrous fruits and larger (12-20 
cm) thin-textured leaf blades with 10-12 pairs of 
2 veins; we place it here in a broader concept of 
G. riparia. Expanding the concept of G. riparia to 
include a greater range of variation is a natural 
consequence of better sampling over a wide range 
of habitats. Unfortunately, this may make the dif- 
ferentiation of other species, such as G. actinos- 
temoides Mull. Arg. and G. dress leri Webster of 
Panama, more difficult. 



124 



FIELDIANA: BOTANY 



Hevea Aublet 

REFERENCES R. E. Schultes, The history of tax- 
onomic studies in Hevea. Bot. Rev. 36: 197-276. 
1970. A brief taxonomic view of the genus Hevea. 
Malaysian Rubber Research & Development Board 
Monograph 14: 1-57. 1990. 

Trees, monoecious, glabrous or puberulent, with whit- 
ish latex; stipules lateral. Leaves alternate, trifoliolate, 
long-petiolate, with a gland at apex beneath petiolule 
attachment; leaflet blades with entire margins, usually 
thin-chartaceous, glabrous or puberulent, pinnately 
veined. Inflorescences axillary, solitary at each node, pa- 
niculate, usually puberulent, flowers in distal cymes with 
a terminal 9 flower and lateral 6 flowers, bracts small. 
Male flowers globose to ovoid in bud, calyx cupulate 
with 5 valvate teeth or lobes, petals absent, disk of 5 
small free or connate glands; stamens united into a col- 
umn, with 1 or 2 whorls of 5 sessile anthers on the 
stamina! column, column extending beyond the anthers; 
pistillode present at apex of column. Female flowers usu- 
ally larger than the male, calyx 5-lobed, petals and stam- 
inodes absent, disk dissected or absent; ovary 3-locular, 
ovules 1/locule, styles short or stigmas sessile. Fruits 
large capsules, 3-lobed in cross-section, oblate to ovoid 
in outline, exocarp slightly carnose, endocarp woody; 
seeds large, mottled, ecarunculate, cotyledons thick. 

A genus of 9-10 species, originally found only 
in the Amazon basin. The following important 
economic species is grown in Central America. 



Hevea brasiliensis (Willd. ex Adr. Juss.) Mull. Arg., 
Linnaea 34: 204. 1865. Siphonia brasiliensis 
Willd. ex Adr. Juss., Euphorb. Gen., t. 12. 1824. 

REFERENCE R. E. Schultes, Studies in the genus 
Hevea HI. Notes on infraspecific variants of Hevea 
brasiliensis (Euphorbiaceae). Econ. Bot. 41:1 25- 
147. 1987. 

Trees up to 30 m tall, leafy stems 4-12 mm thick, 
glabrous or with short (0.4 mm) thin hairs; stipules ca. 
2 mm long, triangular-subulate, thick. Leaves quite vari- 
able in size, petioles 9-38 cm long, 2-5 mm thick, often 
becoming constricted at base and apex when dried, apical 
gland 1.3-4 mm wide, reniform, petiolules 8-18 mm 
long, 1-2.2 mm thick; leaflet blades 8-22 cm long, 3- 
10 cm wide, elliptic to obovate, apex acuminate, base 
acute, 2 veins 1 1-20/side, 3 veins subparallel, 4 veins 
partly parallel. Inflorescences 8-20 cm long, racemose 
panicles with alternate lateral branches 5-45 mm long, 
minutely whitish puberulent; 6 flower buds 3-4 mm long; 
distal 9 flowers 4-8 mm long, calyx lobes 2^4 mm long; 
ovary ca. 1 .7 mm long, ovoid with sessile stigmas, dense- 
ly sericeous. Fruits ca. 4 cm long, 4-6 cm wide, oblate 
and 3-lobed, smooth and glabrous, on peduncles ca. 12 
cm long. 



Hevea brasiliensis (Para rubber, cancho de Bra- 
zil) is the world's most important source of natural 
rubber. Malaysia, Indonesia, and Brazil are the 
major areas of production. For good production, 
the trees require warm (24-3 2C) temperatures and 
an even annual rainfall of over 1900-2500 mm/ 
year with a short dry period (Cobley & Steele, 
1976). In Central America, the species is found in 
gardens and plantings at 20-1100 m elevation, 
with flowering primarily in February-March. The 
long-petiolate trifoliolate leaves, milky latex, fra- 
grant yellowish flowers with a basally united calyx 
(no corolla), unusual androecium, and large three- 
lobed fruits distinguish these plants. 



Hieronyma 

See Hyeronima. 
Hippomane Linnaeus 

Small or medium-sized trees, monoecious, glabrous 
throughout, with caustic whitish latex; stipules paired at 
the leaf bases, small, caducous. Leaves alternate, simple, 
petioles with a glandular area at the apex, lamina ovate, 
subentire with slightly raised gland-tipped serrations, 
pinnately veined. Inflorescences terminal, solitary, spi- 
cate, bisexual with l(-2) subsessile 9 flowers at the base, 
<5 flowers 8-many in alternate sessile glomerules along 
the thick rachis, bracts higlandular at the base; 9 flowers 
subsessile. Male flowers with a small calyx usually sep- 
arating into 2 (3) parts, petals and disk absent; stamens 
2, exserted, united at the base to form a short column, 
anthers dehiscing longitudinally and extrorse; pistillode 
absent. Female flowers with 2-3 imbricate sepals, petals, 
disk and staminodes absent; ovary with 6-10 locules, 
styles short united at base, with 2 recurved simple 
branches, ovules 1 /locule. Fruits drupaceous, globose to 
oblate, smooth, green becoming yellowish, indehiscent; 
seeds ovoid-compressed, ecarunculate. 

A genus of three species, one widespread and 
the others endemic in the West Indies. Our species 
is quite distinctive, but this genus may be difficult 
to separate from its close relatives; see the dis- 
cussion under Sapium. 

Hippomane mancinella L., Sp. PI. 1 1 9 1 . 1 753. Fig- 
ure 32. 

Small or medium-sized trees, 2-8(-18) m tall, often 
with a spreading rounded crown, bark scaly grayish to 
reddish brown, leafy stems 2-5 mm thick, glabrous, lon- 
gitudinally striate, lenticels 0.4-1.2 mm diam., rounded 
with an annular rim and central brownish area, sap whit- 
ish, caustic; stipules 1-2 mm long, 1 mm broad at the 
base, triangular, brown, caducous. Leaves evergreen, pet- 
ioles 1248 mm long, 0.4-1 mm thick, glabrous, with a 



BURGER & HUFT: FLORA COSTARICENSIS 



125 



darkened flat or elevated-crateriform gland at the apex; 
leaf blades 3-8 cm long, 2-5 cm broad, ovate to ovate- 
oblong or ovate-orbicular, apex obtuse to acute with a 
minute gland tip, margin with 8-20 teeth/side, ca. 0.3 
mm high and gland-tipped, drying stiffly chartaceous, 
lustrous above, glabrous, 2 veins 7-9/side. Inflores- 
cences 2.8-7 cm long, 3-6 mm wide distally, glabrous, 
peduncles 0.5-2 mm long, rachis 1-1.5 mm thick, green- 
ish; 9 flowers on pedicels 0.3-1 mm long, $ glomerules 
2-3 mm broad with 3-12 congested subsessile flowers, 
yellow, distal bracts ca. 0.7 x 1.5 mm with 2 lateral flat 
glands basally. Male flowers ca. 2 mm long, calyx 0.5- 
0.9 mm long, breaking irregularly into 2 or 3 parts, fil- 
aments slightly exserted, anthers ca. 0.5 mm long. Fe- 
male flowers with a cupulate calyx ca. 2 mm high, ir- 
regularly dehisicent, ovary ca. 2 mm long and at first 
enclosed by the calyx, style column 0.2-0.5 mm long, 
style branches recurved. Fruits 1.4-2 cm long, 1.8-2.5 
cm wide (dried), oblate to subglobose, resembling a small 
green apple; seeds ca. 6 mm long. 

Found only along ocean shores and swamps on 
both the Caribbean and Pacific coasts, 0-20 m 
elevation. This species sometimes forms mono- 
specific stands at the edge of the beach. While 
frequent along the Pacific, this species has not been 
collected along Costa Rica's Caribbean shore. 
Flowering in March-April and September-De- 
cember; fruiting in August-September and De- 
cember-May. The species ranges from Florida, the 
Bahamas, West Indies, and Mexico to Colombia. 

Hippomane mancinella is recognized by its sea- 
side habitat, toxic sap, small lustrous ovate leaves 
with finely crenulate-serrate gland-tipped margins, 
spicate bisexual inflorescences, and fruits resem- 
bling small apples. The sap is highly caustic and 
will cause severe inflammation of sensitive skin 
or tissues; it may cause blindness. Smoke from the 
burning wood can be dangerous to the eyes. The 
tree is common at Playas de Manuel Antonio where 
visitors are warned of the tree's toxicity. It is called 
manzanillo de playa, manzanita de playa, and 
"manchineel." 



Hura Linnaeus 

Small to very large trees, monoecious, larger trunks 
to over 1 m diam., bark with hard broad-based sharp- 
tipped conical spines, sap clear; stipules paired, imbri- 
cate and covering the shoot apex (but not leaving a scar 
around the stem), caducous. Leaves alternate, simple, 
petioles long and with 2 rounded glands at the apex, 
blades usually broadly ovate and subcordate, margins 
bluntly serrate, glabrous or pubescent beneath, pinnately 
veined. Inflorescences unisexual, glabrous, $ terminal, 
long-pedunculate, spicate with a thick-fleshy rachis with 
crowded sessile flowers in a narrow cone-like arrange- 
ment, bracts membranaceous; 9 flowers solitary in the 
axils of distal leaves (rarely at the base of <5 spikes), ped- 



icels thick. Male flowers at first enclosed by a thin bract 
and rupturing at anthesis, calyx united to form a mem- 
branaceous denticulate cup, petals, disk and pistillode 
absent; stamens many and united, filaments absent, an- 
thers sessile, verticillate and laterally compressed in 2- 
10 superposed whorls on a thick central column trun- 
cated distally, dehiscing longitudinally and extrorse. Fe- 
male flowers glabrous, calyx cupulate and truncate, co- 
rolla, staminodes and disk absent; ovary 5-20-locular, 
ovules 1/locule, styles united into a long thick column, 
style branches as many as the locules and separate be- 
yond the truncated webbed radiating lobes. Fruits cap- 
sular, large and oblate with a depressed apex, with as 
many lobes as locules, cocci dehiscing explosively, col- 
umella persisting; seeds laterally compressed, ecarun- 
culate, cotyledons flat, rounded. 

A tropical American genus of two species. The 
cone-like male inflorescences, with flowers having 
superposed verticels of anthers on a thick axis, are 
among the most unusual in angiosperms. Hura 
polyandra Baill. differs from our species in having 
longer male flowers with 5-10 verticels of anthers 
on the thick staminal column. This makes the 6 
inflorescences look very different from those of//. 
crepitans. In addition, the leaves of//, polyandra 
appear to have more prominent serrations. Both 
species were stated to occur in Costa Rica (Stan- 
dley, 1937; Webster & Burch, 1967), but we be- 
lieve that these reports were based on misdeter- 
rn inations; we have seen no material of H. po- 
lyandra from south of Honduras. 



Hura crepitans L., Sp. PI. 1008. 1753. Figure 32. 

Trees 5-35 m tall, larger trunks to over 1.5 m diam., 
with hard conical broad-based spines 1-3 cm high on a 
pale gray bark, leafy internodes 3-1 2 mm thick, glabrous; 
stipules 6-12 mm long, 1-4 mm broad at the base, at 
first enclosing the shoot apex, usually glabrous or mi- 
nutely (0. 1 mm) ciliolate along the margin, drying red- 
dish brown, caducous. Leaves deciduous, petioles 4- 
15(-20) cm long, 1.3-3 mm thick, often drying with a 
contracted area 6-10 mm long near the base, with 2 
raised dark-drying glandular areas at the apex adaxially; 
leaf blades 5- 18(-25) cm long, 4-1 4(- 17) cm broad, ovate 
to broadly ovate or ovate-orbicular (ovate-elliptic), apex 
acuminate with a tip 5-20 mm long, margin serrate or 
rounded-crenate with 9-20 gland-tipped teeth on each 
side, base rounded and cordate to subcordate, drying 
chartaceous and greenish, glabrous above, with thin 
straight or crooked hairs 0.5-1.5 mm long on the major 
and minor veins beneath, venation pinnate with 7-20 
2 veins/side, 3 veins subparallel. Male inflorescences 
with peduncles 2-16 cm long, 2-3 mm thick, spikes 2- 
5 cm long, 12-18 mm thick, conical at first with spirals 
of 60-80 congested bract-enclosed flower buds, red; $ 
flowers 3-5 mm long, 2-3 mm diam., borne on thick 
short (1-2 mm) pedicels, cylindrical-obovoid with a thick 
central axis, truncated and 1-2 mm wide distally, calyx 



126 



FIELDIANA: BOTANY 



ca. 1 mm long; stamens in 2 (rarely 3) verticels of yellow 
anthers with ca. 12-15 anthers/ whorl, anthers of smaller 
whorl 0.3-0.6 mm long, the larger whorl 0.5-1.2 mm 
long. Female inflorescences of solitary dark red flowers, 
pedicels 1-5 cm long, 3-4 mm thick, becoming woody 
in fruit; 9 flowers 4-6 cm long, glabrous, calyx tube 3-8 
mm long, entire distally, stylar column 3-5 cm long, 1 .3- 
2 mm thick (larger near base and apex), style branches 
forming a truncated apex with united radiating tips (par- 
asol-like), free digitate style branches 4-10 mm long. 
Fruits 3-5 cm high, 6-1 1 cm broad, rounded-oblate, 
depressed in the center around the apex (pumpkin-like), 
breaking up into ca. 30 woody crescent-shaped segments 
2-5 mm thick, columella ca. 3 cm long with broad apex 
and base; seeds ca. 15/fruit, 1.5-2 cm diam., 5-8 mm 
thick, lenticular with flattened sides, smooth and pale 
yellowish. 



Trees of both evergreen and deciduous forest 
formations in both the Caribbean and Pacific low- 
lands, 0-600 m elevation. Probably flowering 
throughout the year (mostly October-November 
in Golfo Dulce [Allen, 1956]; April-December at 
Barro Colorado Island [Croat, 1978]); fruiting in 
January-April. The species ranges from Nicaragua 
to Peru, Brazil, and the West Indies. 

Hura crepitans is recognized by its large trunks 
with thick conical spines, long-petiolate broadly 
ovate-cordate leaves with crenate/serrate margins, 
large solitary dark red 9 flowers with little perianth 
and expanded parasol-like stylar apex, the unique 
$ flowers, and 1 5-seeded fruits. After explosive 
dehiscence, the fruits produce many C-shaped 
woody fragments. The sap is inflammatory to sen- 
sitive skin; the wood is used for making boxes and 
inexpensive furniture. The seeds are poisonous but 
are used in small amounts as a purgative (Allen, 
1956; Standley & Steyermark, 1949). These large 
impressive trees are called havillo, jabillo, javillo, 
and "sandbox tree." Pittier (1957) reported the 
following Indian names: Bribri: Betshur; Brunka: 
Tsu-kra; Terraba: Ui (tirub); and Igun. 



Hyeronima Fr. Allemao 

REFERENCE P. Franco R., The genus Hyeron- 
ima (Euphorbiaceae) in South America. Bot. Jahrb. 
Syst. 111:297-346. 1990. 

Trees or shrubs, dioecious, wood hard, surfaces with 
flat rounded peltate many-rayed hairs, straight hairs also 
sometimes present; stipules present or absent, decidu- 
ous. Leaves alternate, petiolate, lacking glands at the 
apex, margins entire, venation pinnate, usually with pel- 
tate and simple hairs. Inflorescences axillary, solitary, >' 
usually somewhat larger and with more branches than 
the S, paniculate with alternate 2 branches, 2 branches 
unbranched and racemose or spicate, bracts small, with 
peltate hairs, pedicels short. Male flowers with cupulate 
calyx, with 3-6 short imbricate lobes, petals absent, disk 
cupulate and thick, annular or lobed; stamens 3-6, op- 
posite the calyx lobes and within the disk, filaments free, 
exserted, anthers with 2 divergent pendulous thecae, de- 
hiscing longitudinally or by pores; pistillode small. Fe- 
male flowers with united calyx, cupulate with 3-6 short 
teeth, persisting in fruit, petals absent, disk thin, cupu- 
late, entire or lobed, staminodes absent; ovary 2- 
(3-)locular, ovules 2/locule, styles short, reflexed, slightly 
bifid. Fruits fleshy, indehiscent, usually 1 -seeded, small, 
exocarp thin, endocarp hard; seed without caruncle, en- 
dosperm carnose, cotlyedons broad flat. 

A genus of ca. 20-30 poorly defined Neotropical 
species. This genus is very closely related to An- 
tidesma of the Old World tropics. The flat peltate 
many-rayed hairs on almost all plant parts, soli- 
tary axillary inflorescences with alternate branches 
that are unbranched, unisexual (dioecious) trees, 
small cupulate calyx, and fleshy fruits with usually 
only one seed make this genus distinctive. Some 
specimens may resemble Croton, but that genus 
usually has unbranched inflorescences and the fruits 
are not fleshy. We follow recent authors regarding 
the spelling of this genus, but note that A. Rad- 
cliffe-Smith has recently proposed conserving the 
spelling Hieronyma in preference to Hyeronima 
(see Taxon 43: 485^86, 1994). 



Key to the Species of Hyeronima 

1 a. Stamens usually 4, pistillode slender and bifid; fruits 3-4 mm long (dried), fruiting mostly in January- 
June; petioles 2-18 cm long; stipules narrow or broadly rounded, 3-15 mm long; rarely found above 
600 m elevation H. alchorneoides 

Ib. Stamens usually 5, pistillode stout, not bifid; fruits 4-6 mm long (dried), fruiting mostly in June- 
January; petioles 0.9-4 cm long; stipules usually absent; 50-2200 m elevation but uncommon below 
500 m . H. oblonga 



Hyeronima alchorneoides Allemao, PI. novas Bra- 
sil (icon.) 1848. Stilaginella laxiflora Tul., Ann. 
Sci. Nat. Bot. Ser. 3, 15: 244. 1851. H. laxiflora 



(Tul.) Mull. Arg., Linnaea 34: 67. 1865. H. tec- 
tissima Standl. & L. O. Wms. (nom. nud.) in 
Allen, Rain Forests of Golfo Dulce 222, pi. 29. 



BURGER & HUFT: FLORA COSTARICENSIS 



127 



1956, without latin description. H. alchor- 
neoides var. stipulosa Franco, Bot. Jahrb. Syst. 
Ill: 321. 1990. Figure 28. 



Trees to 40 m tall, trunks 20-150 cm diam., with 
buttresses to 1.3 m high, dioecious, leafy stems 2-15 
mm thick, densely covered with peltate appressed hairs 
0.1-0.3 mm diam.; stipules 3-15 mm long, ca. 1-2 mm 
wide and lanceolate or broadly rounded and to 2 cm 
wide. Leaves with petioles 2-9(-18) cm long, 1.2-3.5 
mm thick, appressed-pubescent, often sulcate above, of- 
ten geniculate at the apex; leaf blades 8-24(-44) cm long, 
5-15(-29) cm wide, broadly elliptic to broadly elliptic- 
oblong, ovate-oblong, or suborbicular, apex acute to cau- 
date-acuminate, tip 3-20 mm long, margin entire, base 
obtuse to rounded and subtruncate, drying thinly to stiff- 
ly chartaceous and dark above, with scattered flat round- 
ed peltate hairs 0.1-0.2 mm wide, more densely pubes- 
cent beneath, thin straight hairs to 1 mm long often 
present along the midvein beneath, 2 veins 4-1 I/side, 
often weakly loop-connected near the margin. Male in- 
florescences 5-15 cm long, open paniculate with 4-9 
simple racemose branches to 10 cm long, ca. 0.7 mm 
thick, bracts ca. 0.7 mm long, broad-based, pedicels 0- 
0.7 mm long, 0.2-0.4 mm thick; 3 flowers with calyx 1- 
1 .3 mm long, ca. 1 .5 mm wide, lobes 4, ca. 0.2 mm long, 
broadly obtuse, surface covered with minute peltate hairs; 
stamens usually 4 in Costa Rica (5-6), filaments 1-1.5 
mm long, anthers 0.3-0.4 mm wide, appearing to open 
by pores, disk annular, pistillode 0.7-1 mm long. Female 
inflorescences 4-10 cm long, with 3-9 alternate branch- 
es, densely covered with peltate hairs, pedicels 0.5-1 mm 
long, 0.3-0.5 mm thick; 2 flowers 1.5-2 mm long, calyx 
0.5-0.8 mm long, lobes minute or obscure, ovary ca. 1 
mm long, exposed in early stages, glabrous or with few 
peltate hairs, styles ca. 0.3 mm long, united at the base. 
Fruits 34 mm long, 2-4 mm diam. (dried), ovoid or 
ellipsoid, becoming red, then purple-black, subtended 
by the persisting calyx ca. 1.5 mm wide; seeds ca. 2 mm 
long. 



Plants of evergreen lowland rain forest forma- 
tions, 5-700(-900) m elevation. Flowering peaks 
are in May-July and November-January (Flores, 
1993, reference below); fruiting in January-July. 
The species ranges from southern Mexico to Peru 
and Brazil. 

Hyeronima alchorneoides is recognized by its 
lowland evergreen forest habitats, long petioles and 
large leaves (on some shoots), flat rounded hairs 
on leaf surfaces, open panicles with unbranched 
lateral branches, small unisexual flowers with cu- 
pulate calyx, and single-seeded fleshy fruits. The 
large size of some individuals, their short buttress- 
es, and the hard reddish wood are additional char- 
acters. Also, old leaves turn bright red and are 
scattered through the crown (Allen, 1956). Leaves 
can vary greatly in size in different collections. 
Plants having broadly rounded stipules and larger 
leaves with more 2 veins have been designated 



as var. stipulosa. The names nanciton (Nicaragua), 
pilon (Costa Rica), and zapatero (Panama) are 
commonly used. For a comprehensive summary 
of names, ecology, morphology, and silviculture 
of this species, see Pilon, by Eugenia M. Flores, 
in Arboles y semillas del Neotropico, 2: 53-73, 
1993. 



Hyeronima oblonga (Tul.) Mull. Arg., Linnaea 34: 
66. 1865, and in DC, Prodr. 15 (2): 271. 1866. 
Stilaginella oblonga Tul., Ann. Sci. Nat. Bot. 
Ser. 3, 15: 248. 1851. S. benthamii Tul., Ann. 
Sci. Nat. Bot. Ser. 3, 15: 247. 1851. H. oblonga 
var. benthamii (Tul.) Muell. Arg. 34: 66. 1865. 
H. guatemalensisi. D. Smith, Bot. Gaz. 54: 24 1 . 
1 9 1 2. H. poasana Standl., Field Mus. Nat. Hist., 
Bot. Ser. 18: 611. 1937. Figure 28. 

Trees 4-25 m tall, larger trunks 20-50 cm diam., wood 
yellowish to reddish brown within, leafy stems 1 .4-6 mm 
thick, densely covered with flat peltate hairs 0. 1-0.3 mm 
diam.; stipules usually absent (rarely to 4 mm long and 
1-2 mm wide). Leaves with petioles 1-4 cm long, 0.8- 
1.7 mm thick, densely covered with appressed peltate 
hairs; leaf blades 4-17 cm long, 2-9 cm wide, elliptic to 
broadly elliptic-oblong or ovate-elliptic, apex short- to 
long-acuminate (caudate-acuminate), margin entire, base 
obtuse to slightly rounded, drying grayish green above 
and brownish beneath, with scattered flat peltate hairs 
above, sparsely to densely pubescent beneath, the peltate 
hairs 0.2-0.3 mm diam., midvein often with straight thin 
hairs to 1 mm long, 2 veins 4-8/side, free or weakly 
loop-connected near the margin. Male inflorescences to 
1 1 cm long, with 1-5 spiciform lateral branches to 9(-l 1) 
cm long, 0.5-0.8 mm thick, densely lepidote, pedicels 
0.2-1.3 mm long, 0.2-0.6 mm thick; <5 flowers mostly 
solitary (2-3), calyx 0.5-1 mm long, 1.2-2 mm wide, 
cupulate, lobes 5-6, 0.1-0.2 mm long, broadly obtuse; 
stamens 5 in ours (4-6), filaments 1-2.2 mm long, an- 
thers 0.2 x 0.4 mm, thecae divergent, disk lobed. Female 
inflorescences 2-8 cm long, with 1-7 lateral spiciform 
branches subtended by oblanceolate bracts 2.5-7 mm 
long, branches to 5 cm long, ca. 1 mm thick, bracteoles 
ca. 0.7 mm long, broad-based, pedicels ca. 1 x 0.4 mm; 
2 flowers solitary, calyx 0.4-0.8 mm long, 1-1.5 mm 
wide, cupulate with 4-5 lobes ca. 0.3 mm long, obtuse; 
ovary ca. 1 x 0.5 mm, exposed in early stages, surface 
dark and glabrous, style column 0.2-0.4 mm long, style 
branches to 0.3 mm long. Fruits 4-6 mm long, 35 mm 
diam., ovoid-ellipsoid, fleshy, becoming yellowish, pur- 
plish red or dark red, pedicels to 2 mm long. 

Plants of evergreen forest formations from (ca. 
100-)500-2400 m elevation. Flowering in Janu- 
ary-September; fruiting in June-January. This 
species ranges from Guatemala to Peru and Brazil. 

Hyeronima oblonga is recognized by its pref- 
erence for montane habitats, the flat peltate many- 
rayed hairs on almost all surfaces, small flowers 



128 



FIELDIANA: BOTANY 



with cupulate calyx, and fleshy one-seeded fruits. 
There is considerable diversity in leaf form, den- 
sity of leaf pubescence, size and branching of the 
inflorescences, and floral morphology and vesture. 
This variation appears to be found throughout 
southern Central America and at all elevations 
(but low-elevation leaves tend to be larger and 
thinner). These conclusions are in agreement with 
those of Franco (cited above), who studied the 
South America material. 



Jatropha Linnaeus 

REFERENCES B. Dehgan & G. Webster, Mor- 
phology and infrageneric relationships of the genus 
Jatropha (Euphorbiaceae). Univ. Calif. Publ. Bot. 
74: 1-73. 1979. B. Deghan, Phylogenetic signifi- 
cance of interspecific hybridization in Jatropha 
(Euphorbiaceae). Syst. Bot. 9: 467-478. 1984. 

Trees, shrubs, or perennial herbs with thick rootstocks 
(annual in /. gossypiifolid), monoecious or dioecious, 
hairs simple or glandular, latex clear or colored; stipules 
present or absent, very variable in form and glandular 
in some species. Leaves alternate (subopposite when 



crowded on lateral shoots), simple, petioles without 
glands, blades very variable in form, often with palmate 
lobes (rarely pinnately lobed), margins entire to dentate, 
often with glands, venation palmate (pinnate), glabrous 
or puberulent. Inflorescences axillary or terminal, soli- 
tary or 2, usually with a prominent peduncle and alter- 
nate or dichotomous branches (corymbiform), bracteate, 
9 flowers terminating proximal nodes and fewer than the 
distal $ flowers in bisexual inflorescences, flowers pedi- 
cellate and usually in distal cymes. Male flowers with 5 
sepals, imbricate in bud, with or without glandular mar- 
gins, petals 5, free or connate to form a short tube, green- 
ish to white or red, longer than the sepals, disk entire or 
of 5 segments; stamens usually 8 (6-14) in 2 whorls (5 
+ 3), anthers dehiscing longitudinally; pistillode small 
or absent. Female flowers with 5 imbricate sepals, petals 
as in the $ flowers, disk annular or dissected, staminodes 
absent; ovary with 3 (1-2) locules, glabrous or hirsute, 
ovules 1/locule, styles free or united, simple or bifid 
distally. Fruits capsules breaking into 3 (1-2) 2-valved 
cocci or somewhat fleshy and tardily dehiscent; seed with 
a usually lobed caruncule, testa crustaceous, smooth, 
endosperm copious, cotyledons broad. 

A genus of ca. 175 species in tropical America, 
Africa, and south Asia. Neotropical species are 
usually found in drier vegetation. A few species 
are popular as ornamentals and some have been 
used for their medicinal properties. 



Key to the Species of Jatropha 

la. Leaves peltate with petiole attached 1-3 cm from edge [stipules branched and drying hard; inflo- 
rescences bright red; grown as an ornamental but wild in Nicaragua] /. podagrica 

1 b. Leaves not peltate, petiole attached to edge of blade 2 

2a. Leaves deeply palmately lobed, sinuses > 60% of the length of the blade 3 

2b. Leaves unlobed or with short lateral lobes, sinuses < 30% the length of the blade 4 

3a. Leaf lobes 3 or 5, petioles and leaf margins with small (0.3-1.5 mm) stalked glands or gland- 
tipped hairs; naturalized weeds or planted for ornament J. gossypiifolia 

3b. Leaf lobes 9 or 1 1 , petioles and leaf margins lacking stalked glands or gland-tipped hairs; planted 
in gardens for ornament J. multifida 

4a. Flowers with dark red petals to 2 cm long; leaves ovate-oblong with pinnate or subpalmate venation; 
garden trees and shrubs or occasionally naturalized in Central America J. integerrima 

4b. Flowers with white or yellowish petals < 8 mm long; leaves ovate to 3-lobed with palmate venation; 
native or naturalized plants in Costa Rica 5 

5a. Common trees often planted in hedges; petals united only at the base, broadly imbricate; leaves 
usually glabrous beneath except for the basal vein axils J. curcas 

5b. Rarely collected trees of northwestern Guanacaste; petals united for about Vs of their length, only 
the distal lobes imbricate; leaves usually with thin hirtellous hairs beneath J. costaricensis 



Jatropha costaricensis Webster & Poveda, Brit- 
tonia 30: 265. 1978. Figure 3. 

Shrubs or small trees 2-5 m tall, dioecious, trunks to 
ca. 20 cm diam., latex reddish, leafy stems hirsutulous 
with brownish hairs ca. 0.3 mm long, glabrescent, terete; 



stipules reduced (ca. 0.5 mm) and gland-like. Leaves with 
petioles (2-)4-9 cm long, 1-1.5 mm thick, without distal 
glands, hirsutulous; leaf blades (4-)9-18(-21) cm long, 
(4-)7-18(-21) cm broad, ovate or with 3 shallow obtuse 
lobes or 3-angled, apex obtuse or acute, margins entire, 
without glands, base truncate to subcordate (cordate), 
drying chartaceous, becoming sparsely hirtellous above, 



BURGER & HUFT: FLORA COSTARICENSIS 



129 



densely hirtellous beneath with thin hairs ca. 0.3 mm 
long, venation palmate with 3 or 5 (7) major veins. Male 
inflorescences terminal or subterminal, 1 or 2, peduncles 
1-8.5 cm long, with several dichotomous hirtellous 
branches, bracts 0.5-1 .5 mm long, lanceolate, entire, hir- 
tellous; 6 flowers on pedicels 0.5-1 mm long, 0.2-0.3 
mm thick, hirtellous, articulated at base; calyx lobes 2- 
3(-4.5) mm long, 0.8-1.5 mm wide, narrowly oblong, 
obtuse to subacute, entire, greenish, corolla 3-6 mm long, 
tube ca. 2.5 mm diam., creamy white, glabrous exter- 
nally, lobes 1-2.5 mm long, disk with 5 segments 0.5- 
0.9 mm diam.; stamens 10 in 2 whorls of 5, staminal 
column ca. 2 mm long, filaments 2-3 mm long, anthers 
0.9-1.5 mm long, 0.5-0.8 mm wide. Female inflores- 
cences a solitary (2) terminal flower, pedicels ca. 1 mm 
long, to 6 mm in fruit; $ flower ca. 8 mm long, calyx 
lobes 5-7 mm long, lanceolate, usually acute, puberulent, 
corolla tube 4.5-6 mm long, lobes 1.8-4 mm long, disc 
with 5 large lobes; ovary 2-3 mm long, smooth, 3-ridged, 
styles ca. 3 mm long, united into a column ca. 1 mm 
long, distally bifid. Fruits 3-3.5 cm diam., columella ca. 
2 cm long, narrowly winged; seeds 1 7-20 mm long, 1 2- 
14 mm thick, ellipsoid-globose, caruncle ca. 1.8 mm 
wide. 

Plants of the seasonally very dry deciduous for- 
ests near the Pacific shore at 5-50 m elevation. 
Flowering in June and August; fruiting in August 
( Webster & Poveda 22160 MO holotype, CR & DUKE 
isotypes). The species is known only from Playas 
del Coco and P.N. Santa Rosa in Guanacaste 
Province, Costa Rica. 

Jatropha costaricensis is recognized by its pal- 
mately veined ovate or three-lobed leaves hirtel- 
lous beneath, short inflorescences, and small flow- 
ers. Herbarium material resembles J. curcas quite 
closely, but the latter has glabrous leaves, except 
for the basal veins beneath. This species and its 
close relatives are another example of the phyto- 
geographic link between the dry deciduous vege- 
tation of northwestern Guanacaste and that of 
similar habitats in Mexico (Webster & Poveda, 
1978). 

Jatropha curcas L., Sp. PI. 1006. 1753. Figure 3. 

Shrubs or small trees 1.5-5(-8) m tall, bark peeling in 
papery scales, sap white or clear, leafy stems 2-13 mm 
thick, glabrous or less often minutely (0.2-0.5 mm) pu- 
berulent; stipules 0.3 mm high, acicular or gland-like, 
caducous. Leaves with petioles 3-15 cm long, 0.7-2.7 
mm thick, usually glabrous except near the base, genic- 
ulate or expanded at the base; leaf blades 7-25 cm long, 
6-2 1 cm wide, ovate to ovate-triangular, unlobed or pal- 
mately 3- (5-, 7-)lobed, lateral lobes 5-35 mm long, api- 
ces obtuse to short-acuminate, margin entire or slightly 
undulate-dentate, base cordate with sinuses 5-22 mm 
deep, drying chartaceous, glabrous above, minutely (0.3 
mm) puberulent along the veins and in the basal vein 
axils beneath, venation palmate with 3(5,7) major veins, 
2 veins 2-3/side of midvein. Inflorescences 5-18(-25) 



cm long, terminal or axillary, solitary, bisexual or uni- 
sexual, peduncles 1.5-10 cm long, 0.8-2 mm thick, gla- 
brous or puberulent, bracts 2-15 mm long, lanceolate, 
without marginal glands, distal axes puberulent. Male 
flowers on pedicels 1-5 mm long, articulate below flower, 
puberulent, sepals 2.8-4.5 mm long, 1.3-1.8 mm wide, 
oblong to obovate, apex rounded, broadly imbricate in 
bud, petals 5-7.5 mm long, lobes obovate-oblong, tube 
villous within, disk segments 0.5-1 mm long; stamens 
8-10, 3-7 mm long, anthers 1-2.2 mm long, pistillode 
absent. Female flowers on pedicels 5-9 mm long, to 1 3 
mm in fruit, sepal lobes ca. 2.5 mm wide, oblong to 
lanceolate, apex obtuse to subacute, petals becoming re- 
curved in fruit and 7-9 mm long; ovary ca. 2.5 x 2 mm, 
glabrous, stylar column 0.5 mm long, style branches 1 .5- 
2 mm long. Fruits 2.5-3 cm long, 2.2-2.5 cm diam., 
ovoid, slightly 3-lobed in cross-section, somewhat fleshy; 
seeds 1 5-22 mm long, ca. 9 mm diam., dark with minute 
longitudinal grooves, caruncle 3-4 mm wide, lobed. 

Plants of seasonally very dry deciduous forest 
formations and widely cultivated, 5-800 m ele- 
vation (to 1 100 m in El Salvador). Flowering and 
fruiting in May-September. Ranging along the dry 
Pacific slope in Central America but widely dis- 
tributed in tropical America. 

Jatropha curcas is recognized by the ovate or 
three-lobed leaves with palmate venation and 
sparse pubescence, the long-peduncled inflores- 
cences, and larger fruit. Coquillo, coquito, and tam- 
pate or tempate are common names for this spe- 
cies, which is often used for hedges. The Brunka 
name is Kuubin-ua (Pittier, 1957). The seeds con- 
tain an odorless oil useful in paint and soap and 
as a lubricant; they have been used as emetics or 
purgatives but are poisonous in large doses. 

Jatropha gossypiifolia L., Sp. PI. 1006. 1753. Fig- 
ure 3. 

Herbaceous subshrubs or short-lived shrubs 0.5-2.5 
m tall, leafy stems 2-7 mm thick, glabrous, terete; stip- 
ules 5-12 mm long, simple or with 1-5 filiform gland- 
tipped segments 0.5-3 mm long, glabrous, persisting. 
Leaves with petioles 1.4-7(-l 1) cm long, 0.7-2 mm thick, 
with simple or branched gland-tipped hairs to 4 mm 
long, thin hairs ca. 0.5 mm long often present along the 
adaxial margin; leaf blades 5-16 cm long, 3-18 cm wide, 
deeply 3- to 5-lobed, central lobe 4-12 cm long, 2-5 cm 
wide at widest part, elliptic to elliptic-obovate, apices 
acute to acuminate, margin dentate, with regularly spaced 
stalked glands 0.2-0.9 mm long, base truncate to sub- 
cordate, lateral lobes somewhat asymmetric, drying thin- 
ly chartaceous, upper surface glabrous or with few thin 
hairs along the veins, short (0.3 mm) thin hairs along 
the leaf edge, venation palmate with 3 or 5 major veins. 
Inflorescences terminal, 1-2, 3-12 cm long, peduncles 
2-6 cm long, with 1-3 alternate branches, pubescent with 
straight thin hairs 0.5-1 mm long, bracts 5-8(-12) mm 
long, lanceolate, with stalked glands along the edge. 
Flowers with sepals 2-8 mm long, 0.7-1.5 mm wide, 



130 



FIELDIANA: BOTANY 



serrate with marginal glands; petals 3-4 mm long, 1.5- 
3 mm wide, obovate with rounded apex, purple or red- 
dish; $ flowers with 8 stamens, filaments 2.2-3 mm long, 
anthers 0.5-0.7 mm long. Fruits ca. 12 mm high, 10-15 
mm diam., oblong, 3-sulcate; seeds 7-8 mm long, 4.5- 
4.7 mm wide, 3-3.5 mm thick, oblong, smooth, caruncle 
2.7-3 mm wide. 

Plants of open weedy sites or near ocean beaches 
in both evergreen and deciduous areas (also cul- 
tivated in gardens), 0-800 m elevation. Flowering 
primarily in May-December. The species is prob- 
ably an introduction in southern Centeral America 
and is widespread as a weed throughout the trop- 
ics. 

Jatropha gossypiifolia is recognized by its short 
stature, three- or five-lobed leaves with deep si- 
nuses, unusual stipules with slender gland-tipped 
axes, and flowers with deep red or purple petals. 
Called frailecillo in Costa Rica; compare species 
of Manihot, which lack the gland-tipped hairs. 



Jatropha integerrima Jacq., Sel. Stirp. PL Amer. 
256, t. 183, f. 47. 1763. J. hastata Jacq., Sel. 
Stirp. PL Amer. 256, t. 173, f. 54. 1763. Fig- 
ure 3. 

Shrubs or small trees 1-4 m tall, leafy stems 2-6 mm 
thick, sparsely puberulent with thin straight hairs ca. 0.5 
mm long, becoming reddish brown, terete; stipules 0.5- 
1 mm long, gland-like or broadly triangular. Leaves with 
petioles 3-8 cm long, 0.7-1.8 mm thick, geniculate at 
base, sparsely puberulent, stipel-like glands to 2 mm long 
often present at apex or along base of blade; leaf blade 
6-15 cm long, 3-8(-l 3) cm wide, oblong or ovate-oblong 
to ovate but sometimes with 1-2 short (ca. 7 mm) or 
prominent (1-2 cm) lateral lobes along the margin in the 
proximal half of the blade, apex acuminate, margin en- 
tire or with a few glands along the basal edge, base round- 
ed and truncate or slightly cordate with a narrow sinus 
2-6 mm deep, drying chartaceous to stiffly chartaceous, 
with short (0.5 mm) straight hairs above, glabrous be- 
neath except in the proximal vein axils, venation sub- 
palmate with 3 (5) major veins, 2 veins 2-5/side of 
midvein. Inflorescences terminal or pseudoaxillary, of- 
ten bisexual, 15-20 cm long, peduncles 10-14 cm long, 
ca. 2 mm thick, with alternate cymose branches 2-7 cm 
long, bracts 3-12 mm long, linear with dark glands along 
the margin, pedicels 5-9 mm long, articulate beneath the 
calyx. Male flowers with calyx 3-5 mm long, lobes 1-2 
mm long, triangular with blunt apex, petals 1 2-22 mm 
long, 8-10 mm wide, obovate with rounded distal mar- 
gin, dark red or rose; stamens 10, staminal column ca. 
4 mm long, filaments ca. 3 mm long, anthers 2.2-3 mm 
long. Female flowers with perianth like that of the $, 
ovary 2-2.5 mm long, glabrous, stylar column ca. 2.5 
mm long, style branches ca. 3 mm long, bifid. Fruits 12- 
13 mm diam., subglobose with truncated apex, longi- 
tudinally 3-sulcate; seeds 9-10 mm long, 5-5.8 mm diam., 
caruncle ca. 3 mm wide, 2-parted. 



Jatropha integerrima appears to have become 
naturalized near Limon and Cahuita and in Hon- 
duras, Nicaragua, and Panama; it is a native of 
Cuba often planted as an ornamental. The ovate- 
oblong leaves with pinnate or subpalmate vena- 
tion on long petioles and conspicuous red petals 
are distinctive. 

Jatropha multifida L., Sp. PL 1006. 1753. 

Shrubs or small treelets 2-3(-6) m tall, leafy stems ca. 
5 mm thick, glabrous; stipules 1-2 cm long, with short 
(1 mm) base and slender branches. Leaves with petioles 
8-18 cm long, 1.5-2.5 cm thick, usually glabrous; leaf 
blades nearly orbicular in general outline but deeply lobed, 
10-25 cm long, 14-24 cm wide, with 9 or 1 1 lobes sep- 
arate almost to the base, central lobe 8-14(-20) cm long, 
1.5-4(-9) cm wide, narrowly elliptic-oblong to oblong- 
linear, apex long-acuminate, margin entire, base of blade 
deeply cordate, venation palmate with 9 or 1 1 major 
veins, webbing often present at the basal vein axils. In- 
florescences terminal or pseudoaxillary, solitary, 20-26 
cm long, umbellate or corymbiform, peduncles 18-23 
cm long, 2-3 mm thick, glabrous, flowers in distal con- 
gested cymes 2-3 cm long and 4-5 cm wide; flowers with 
deep red or scarlet corollas. 

Jatropha multifida, the "coral plant," is often 
grown in gardens as an ornamental. It has not been 
reported as native or naturalized in Central Amer- 
ica. The deeply 9- or 1 1 -lobed leaves and red or 
scarlet flowers are distinctive. 

Jatropha podagrica Hook., Bot. Mag. 74, t. 4376. 
1848. 

Small shrubs with swollen base and few branches, 0.3- 
l(-2) m tall, leafy stems 8-14 mm thick, glabrous, with 
large leaf scars and persisting stipules producing a com- 
plex surface; stipules 3-6 mm long, with 3-10 glandular 
branches, becoming hard. Leaves peltate, petioles 5-20 
cm long, 1.5-4 mm thick, glabrous; leaf blades 7-20 cm 
long, 6-16 cm wide, broadly ovate in outline with 3 (5) 
shallow to deep sinuses, apices of the lobes subacute, 
margins entire, base rounded with petiole attached 1-6 
cm from the proximal margin, glabrous, venation pal- 
mate with 5 or 7 major veins. Inflorescences to 26 cm 
long, bright red or orange, peduncle to 20 cm long, flow- 
ers in a compact corymb-like arrangement of dichoto- 
mous/trichotomous branching, glabrous; 6 flowers with 
small (0.5 mm) calyx lobes and oblong petals 3-6 mm 
long, bright red or orange. Fruits ca. 16 mm long, 12 
mm diam., oblong with truncated apex, smooth, green; 
seeds ca. 12 x 6 mm. 

Jatropha podagrica is often planted in gardens 
as an ornamental throughout the tropics. The short 
thick stem from an enlarged base, few lateral 
branches, slightly succulent peltate leaves, and 
bright red inflorescences give it a very distinctive 



BURGER & HUFT: FLORA COSTARICENSIS 



131 



appearance. It is called copa del rey, ruibarbo, 
"white rhubarb," and "purging nut." This species 
is not known from the wild in Costa Rica but is 
found among rocky outcrops at 800-950 m ele- 
vation near Esteli in northwestern Nicaragua. It 
may also be native to deciduous areas in Guate- 
mala and Honduras. 



Mabea Aublet 

REFERENCES M. J. Huft, Notes on Mabea (Eu- 
phorbiaceae) in Central America, together with 
comments on sect. Apodae in Brazil. Phytologia 
62: 339-343. 1987. K. E. Steiner, Pollination of 
Mabea occidentalis (Euphorbiaceae) in Panama. 
Syst. Bot. 8: 105-117. 1983. 

Shrubs or small trees, sometimes with scandent 
branches, monoecious, stems with whitish sap (not toxic), 
branched hairs sometimes present; stipules present or 
absent. Leaves alternate, simple, petioles without glands, 
blade with gland-tipped serrations or entire, pinnately 
veined, often glaucous beneath. Inflorescences terminal 
or axillary, racemose or paniculate, with long flexuous 



central rachis, many-flowered, usually bisexual (rarely 
unisexual open panicles of few 2 flowers), 2 flowers 1- 
1 5 at proximal nodes of the rachis, bracts subtending 
solitary flowers, usually biglandular; $ flowers long-ped- 
icellate and usually borne on 2 peduncles in umbellate 
groups of 3 (1-5) and subtended by a biglandular bract 
(the many $ flower groups sessile on a single unbranched 
racemose rachis in our species). Male flowers with 3-5 
imbricate sepals, open before anthesis, petals and disk 
absent; stamens 10-70, anthers appearing to be sessile 
on a conical or convex receptacle, dehiscing longitudi- 
nally and extrorse; pistillode absent. Female flowers with 
3-6 unequal sepals, imbricate and acute, petals, disk and 
staminodes absent; ovary 3-locular, stylar column long, 
style branches 3, simple, ovules 1/locule. Fruits capsular, 
rounded or 3-lobed and separating explosively into 3 
2-valved cocci, columella persistent; seeds with a carun- 
cle, smooth or warty, endosperm carnose, cotyledons 
broad, flat. 

A Neotropical genus of 40-50 species, mostly 
South American. The genus is distinctive because 
of its racemose inflorescences and the small cone- 
like androecium covered with many sessile an- 
thers. This genus has recently been studied by H.- 
J. Esser (HBG). 



Key to the Species of Mabea 

la. Anthers 3-6/flower; inflorescences usually more than 1/branchlet, terminal and axillary, < 10 cm 
long, apparently erect; plants becoming trees to 30 m tall; leaves glabrous beneath, 5-1 1 cm long 
M. excelsa 

Ib. Anthers 20-30/flower; inflorescences usually solitary and terminal on the branchlet, > 10 cm long, 
usually pendulous; plants to 7 (rarely 20) m tall; leaves glabrous or scurfy pubescent beneath, 5-23 
cm long M. occidentalis 



Mabea excelsa Standl. & Steyerm., Publ. Field 
Mus. Nat. Hist., Bot. Ser. 23: 123. 1944. Figure 
26. 

Trees 5-30 m tall, leafy twigs 1.2-4 mm thick, gla- 
brous; stipules 0.5-1 mm long, triangular, caducous. 
Leaves with petioles 4-13 mm long, glabrous; leaf blades 
5-11 cm long, 1.5-4.5 cm wide, oblong to oblong-lan- 
ceolate, apex caudate-acuminate to acuminate, margins 
with minute (0.1-0.2 mm) serrations, base rounded to 
obtuse, drying chartaceous, lustrous above and glaucous 
beneath, glabrous on both surfaces, 2 veins 10-18/side, 
3 veins conspicuous. Inflorescences terminal or axillary, 
entirely <S or bisexual with 1-3 9 flowers at the base, 
panicles of thyrses, thyrses 3-8 cm long, 5-12 cm wide, 
short-pedunculate, densely puberulent. Male flowers in 
small sessile 3-flowered umbels (triads), subtending bracts 
with 2 oblong glands 0.7-1 long, not raised above the 
axis of the thyrse; calyx 5-lobed, lobes to 0.8 mm long, 
unequal; stamens 3-6. Female flowers subtended by ob- 
long cglandular bracts ca. 0.8 mm long, peduncles ca. 5 



mm long; calyx 6-lobed, 1.5-2.3 mm long, lobes acu- 
minate; styles 6-8 mm long, connate, ca. Vi their length. 
Fruits 12-14 mm long, 12-15 mm diam., ovoid to sub- 
globose, slightly 3-lobed, minutely and densely puber- 
ulent, columella ca. 14 mm long, broadly 3-winged (ca. 
4 mm wide) except near the base; seeds 7-10 mm long, 
6-7 mm wide, ca. 6 mm thick. 



Plants of evergreen forest formations on both 
the Caribbean and Pacific slopes, 300-900 m el- 
evation. Flowering in May-July; fruiting in No- 
vember-December. The only Costa Rican collec- 
tions seen are Herrera & Martinez 2273 CR, MO, 
and Saenz & Nassar 129 usj. The species ranges 
from southern Mexico to southern Costa Rica. 

Mabea excelsa is recognized by its glabrous veg- 
etative parts, paniculate arrangement of distal 
fruits, and tall stature. It is a rarely collected spe- 
cies. 



132 



FIELDIANA: BOTANY 



Mabea occidental is Bentham, Hooker's J. Hot. 6: 
364. 1854. Figure 31. 

Small trees or shrubs, 2-7 (rarely 20) m tall, wood 
hard and yellowish, branches usually slender, leafy stems 
1 .2-4 mm thick, glabrous or with short (0.2 mm) branched 
reddish brown hairs, terete, pale to dark brown; stipules 
not seen (ca. 5 mm long and linear according to Croat 
[1978]), caducous, stipule scars 0.5-2 mm wide. Leaves 
with petioles 4-14 m long, 1-1.8 mm thick, glabrous or 
with short reddish hairs; leaf blades 5-18(-25) cm long, 
2-6(-9) cm wide, oblong to narrowly oblong, elliptic- 
oblong or ovate-oblong, apex acuminate to caudate-acu- 
minate, narrow tip 8-16 mm long, margins subentire or 
with rounded serrations 20-43/side, base obtuse to 
rounded and subtruncate, drying stiffly chartaceous, gla- 
brous and lustrous above, glabrous or with scurfy reddish 
hairs beneath, 2 veins 8-16/side (more when the prom- 
inent intermediate 2 veins are counted), loop-connected 
2-8 mm from the leaf edge, central 2 veins arising at 
angles of 60-80. Inflorescences bisexual and raceme- 
like panicles with a single unbranched axis (but with 
occasional unisexual open panicles of 3-8 2 flowers), 12- 
45 cm long and pendulous, peduncles to 30 cm long, 
glabrous or reddish puberulent; 9 flowers 3-14, each sub- 
tended by a bract 3-9 mm long, lanceolate, 2 basal glands 
present or absent, pedicles 6-14 mm long; 6 flowers usu- 
ally 3 borne on short (1-5 mm) 2 peduncles often en- 
closed by a narrowly convolute bract with 2 oblong glands 
1.2-3 mm long, pedicels 4-22 mm long, 0.2-0.3 mm 
thick, sometimes articulate, minutely papillate-puberu- 
lent. Male flowers reddish or purple, 2-3.5 mm long, 
sepals 3-5, 0.5-1.5 mm long, united at the base and 
forming a shallow cup for the cone-like androecium; 
stamens ca. 20-30, closely crowded on a rounded or 
conical base (1.5-2.5 mm long, 2 mm broad), anthers 
sessile, 0.4-0.6 mm long, covering the surface of the 
receptacle. Female flowers with ca. 6 sepals 2.5-5 mm 
long, 1.2-1.5 mm broad at the base, ovate to lanceolate 
and acute, minutely (0.05 mm) papillate-puberulent; 
ovary 2-4 mm long, densely papillate-puberulent, style 
column 1 1-20 mm long, 0.4-0.6 mm thick, style branch- 
es 4-1 1 mm long. Fruits 10-14(-18) mm long, 12-18(- 
22) mm broad, slightly 3-lobed, green tinged with red, 
surface minutely papillate-puberulent, outer wall of cocci 
0.7-2 mm thick, columella 7-10(-15) mm long, ex- 
panded distally above the 2 mm base; seeds 7-10 mm 
long, 6-7 mm broad, 4.5-6 mm thick, oblong, dark and 
lustrous, caruncle 1-1.5 mm high at apex of seed. 



Plants of lowland evergreen rain forest forma- 
tions of both Caribbean and Pacific slopes and in 
moist shaded sites in deciduous formations, 0- 
1 000 m elevation (but rarely collected above 200 
m in Costa Rica). Flowering throughout the year 
(mostly in November-May); fruiting throughout 
the year. The species ranges from Mexico to Am- 
azonian Brazil. 

Mabea occidentalis is recognized by its pendu- 
lous racemose inflorescences, long-styled female 
flowers and many distal male flowers usually borne 
in threes on short peduncles subtended by biglan- 



dular bracts, and the unusual androecium. The 
distinctive pendulous inflorescences have been re- 
ported to be pollinated by small nocturnal mam- 
mals (see references under genus). The foliage is 
distinctive because of the usually oblong leaf blades 
with caudate-acuminate apex and 2 veins loop- 
connected near the margin. Recent collecting has 
demonstrated that individuals of this species vary 
greatly, regarding both vegetative and floral mor- 
phology. Such a broad pattern of variation con- 
tradicts the assignment of some Costa Rican col- 
lections to M. montana Mull. Arg. This species 
has been called higuera and kurinwacito in eastern 
Nicaragua. 

Manihot Miller 

REFERENCE D. J. Rodgers & S. G. Appan, Ma- 
nihot and Manihotoides (Euphorbiaceae), a com- 
puter-assisted study. Fl. Neotropica, monogr. 13: 
1-272. 1973. 

Herbaceous subshrubs, shrubs, small trees, or vines, 
monoecious (dioecious), branching often dichotomous 
or trichotomous, stems usually with whitish latex, roots 
often with tubers, hairs simple, vegetative parts often 
with cyanogenic glycosides; stipules small, deciduous. 
Leaves alternate, simple but often very deeply lobed and 
almost trifoliolate or palmately compound, petiolate to 
subsessile, blades with stipels at base (foliar glands ab- 
sent), margins entire to serrate or lobed, glabrous to pu- 
berulent, often with abaxial surfaces waxy-glaucous, ve- 
nation palmate in lobed leaves or pinnate in unlobed 
leaves. Inflorescences terminal or pseudoaxillary, soli- 
tary or several, racemose or paniculate, usually bisexual, 
2 flowers usually proximal, $ flowers at central and distal 
nodes, bracts and bracteoles small, flowers usually on 
prominent pedicels. Male flowers glabrous or puberulent 
externally, calyx petaloid, usually united in the lower 
part to form a tube, lobes 5, imbricate in bud, petals 
absent, disk large and intrastaminal, with 5 bifid lobes 
(often appearing 10-lobed); stamens usually 10 in 2 un- 
equal series of 5 longer and 5 shorter free filaments, 
anthers versatile, introrse, dehiscing longitudinally, pis- 
tillode absent or minute. Female flowers protogynous, 
glabrous or puberulent, calyx petaloid, usually with 5 
sepals united only at or near the base, petals absent, disk 
thick and fleshy, subtending the ovary, entire or lobed, 
staminodes absent; ovary smooth or ribbed, 3-locular, 
ovules 1/locule, styles 3, short, united at the base, style 
branches broadly dilated and multilobed. Fruits capsu- 
lar, smooth or with longitudinal wings, breaking into 3 
2-valved cocci, columella often persistent; seeds smooth 
with thin-crustaceous testa, carunculate, endosperm co- 
pious. 

A Neotropical genus of 60-90 species with the 
majority of species in South America. The genus 
ranges from southern Arizona to Argentina, but 
the cultivated M. esculenta is now found through- 



BURGER & HUFT: FLORA COSTARICENSIS 



133 



out the tropics and subtropics. Manihot is best 
represented in seasonally deciduous areas, with 
centers of species diversity in east-central Brazil 
and central and western Mexico. Unusual varia- 
tion within species and extensive hybridization 
between the cultivated plants and wild species have 
made this a taxonomically difficult genus. In ad- 
dition to the important tuber crop (M. esculenta), 
M. glaziovii is the source of Ceara rubber and oil 
seeds. 



The genus is recognized by the larger flowers 
with a single corolla-like perianth whorl, presence 
of palmately lobed leaves (that may appear to be 
palmately compound with deep narrow sinuses), 
glaucous waxy surfaces on the undersides of leaves, 
whitish sap, and presence of cyanogenic glucosides 
that readily break down to form the poisonous 
prussic acid (HCN). Compare Jatropha and Cni- 
doscolus. 



Key to the Species of Manihot 

la. Vines, lianas, or shrubs with clambering branches; leaf lobes not more than 3; fruit surface smooth; 
calyx of $ flowers 6-18 mm long; uncommon native plants [in evergreen lowlands, usually minutely 
puberulent] M. brachyloba 

Ib. Erect shrubs or treelets, branches not clambering; leaf lobes 311; fruit surfaces slightly rugose and 
often longitudinally ridged; <5 calyx 5-13 mm long; common cultivated, escaped or less common 
native plants 2 

2a. Leaves peltate or subpeltate, 3-5-lobed with deep sinuses [small trees planted for ornament] 

M. glaziovii 

2b. Leaves not peltate (sometimes subpeltate in M. esculenta), the petioles usually attached at the lamina 

. 3 



edge 



3a. 



Fruits without prominent longitudinal ridges or wings; nodes not thickened; leaves glabrous, leaf 
lobes often with prominent sinuses and lobes along the margins, leaf blades never with the margin 
extending around the apex of the petiole (not subpeltate); wild plants of the deciduous and partly 

deciduous Pacific slope M. aesculifolia 

3b. Fruits with longitudinal ribs or wings; nodes usually thickened; leaves glabrous or puberulent, leaf 
lobes lacking prominent lateral sinuses and lobes along the margins, leaf blades sometimes with leaf 
margin extending around the petiole apex (subpeltate); cultivated and naturalized plants in many 
habitats . . M. esculenta 



Manihot aesculifolia (H.B.K.) Pohl, PI. Bras. Ic. 
1: 55. 1827. Jatropha aesculifolia H.B.K., Nov. 
gen. sp. 2: 85, pi. 109. 1857. M. gualanensis 
Blake, Contr. U.S. Natl. Herb. 24: 13. 1922. 
Figure 1. 

Shrubs or small treelets, 1-7 m tall, trunks to 10 cm 
diam., leafy stems 1.5-6 mm thick, glabrous; stipules 2- 
9 mm long, often laciniate, caducous. Leaves usually 
palmately lobed, petioles 4-20 cm long, 1-2.5 mm thick, 
glabrous, often bent at apex and base, often with a rugose 
gland-like area at the apex (on blade); leaf blades deeply 
divided into (3-)5-9(-l 1) lobes (sometimes simple near 
the inflorescences), middle leaflets 5-18(-25) cm long, 
1.3-7(-10) cm wide, narrowly elliptic-oblong, narrowly 
elliptic, obovate or pandurate with prominent lateral 
lobes, apex acute to acuminate, margin entire or more 
often with 1-3 lateral lobes and broad sinuses, gradually 
narrowed to the base of the sinuses, lateral lobes often 
l /2 the size of the middle lobe, drying membranaceous to 
thin-chartaceous, glabrous above and below (puberulent 
at the base adaxially). Inflorescences terminal or pseu- 
doaxillary, 4-30(-45) cm long, to 25 cm wide, paniculate 
with racemose lateral branches to 1 5 cm long, often with 



many (> 50) flowers, glabrous, bracteoles 1-3 mm long, 
<J pedicels 7-12 mm long. Male flowers pale green to 
yellowish, buds ca. 8 mm diam., glabrous on the exterior, 
calyx 9-14 mm long, tubular, lobes 6-8 mm long; sta- 
mens 9-13 and 7-8 mm long, anthers 2.3-3 mm long. 
Female flowers yellowish, glabrous externally, calyx 6- 
1 2 m long, lobes 4-6 mm long, disk 2-3 mm diam.; pistil 
6-9 mm long, ovary 2.8-4 mm long, 2.2-3.6 mm diam. 
Fruits 13-15 mm long, 14-17 mm wide, rounded-ob- 
long, surface rugose with weakly developed longitudinal 
ridges; seeds 9-1 1(-1 3) mm long, 6.5-8.5(-10) mm wide, 
3.8-5.3 mm thick, lenticular in cross-section with prom- 
inent lateral margins, surface uniform or mottled, ca- 
runcle 3-3.2 mm wide. 



Plants of seasonally deciduous and partly de- 
ciduous forest formations of the Pacific slope (rare- 
ly collected in the evergreen Caribbean lowlands), 
0-1 100 m elevation. Flowering in May-October. 
The species ranges from Mexico and Guatemala 
along the Pacific slope to Panama. 

Manihot aesculifolia is recognized by its deeply 
palmately lobed leaves often with pandurate or 



134 



FIELDIANA: BOTANY 



lobed margins, lack of pubescence, larger inflores- 
cences with many flowers, larger <5 flowers, and 
rugose fruit. This species is closely related to M. 
esculenta (q.v.) but differs in the verrucose waxy 
surface on the leaf undersides and in characters of 
the key. It is often called yuca de monte. This 
species probably includes material Standley (1937) 
ascribed to M. carthaginensis (Jacq.) Mull. Arg., 
a species of northernmost South America and ad- 
jacent islands. 

Manihot brachyloba Mull. Arg. in Mart., Fl. Bras. 
11 (2): 451. 1874. Figure 1. 

Vines, lianas, or shrubs with clambering branches, 1- 
12 m high, leafy stems 1.3-6 mm thick, minutely pu- 
berulent with thin whitish hairs ca. 0.2 mm long; stipules 
0.5-1 mm long, appressed, puberulent. Leaves usually 
with deep sinuses and almost trifoliolate, petioles 4-13 
cm long, 0.6-1.4 mm thick, minutely puberulent, often 
geniculate at base and apex, small (0.5 mm) gland-like 
structures sometimes present above the apex; leaf blades 
usually deeply 3-lobed, central lobe 5-13 cm long, 2.4- 
4.5 cm wide, elliptic-ovate to elliptic-oblong or lanceo- 
late, apex acuminate, margin entire, gradually narrowed 
to the base of the sinuses, lateral lobes slightly asym- 
metric (simple leaves with base rounded), drying mem- 
branaceous to chartaceous, glabrous above, glabrous or 
minutely (0.1-0.2 mm) puberulent beneath, 2 veins 9- 
1 I/side of midvein. Inflorescences pseudoaxillary or su- 
praaxillary, 1-3, 3-9 cm long, racemose, minutely pu- 
berulent, pedicels to 1 5 mm long. Male flowers yellow- 
ish, calyx 6-18 mm long, 4-7 mm diam., lobes 4-9 mm 
long, disk 1-2 mm high, 2.5-4 mm diam., with 10 round- 
ed lobes; filaments to 5 and 9 mm long. Female flowers 
with sepals 8-1 2 mm long, yellowish; pistil 5-6 mm long, 
ovary subglobose, stylar column ca. 1 mm long. Fruits 
ca. 15 mm long, 20 mm diam., globose-oblate, surfaces 
smooth or muricate; columella ca. 1 1 mm long; seeds 
10-12 mm long, ca. 9 mm wide, 6-7 mm thick, surface 
lustrous, caruncle 3-3.5 mm wide. 

Plants of evergreen rain forest formations on 
both the Caribbean and Pacific slopes, 20-600 m 
elevation. Flowering in June-September; fruiting 
in November. The species ranges from northern 
Costa Rica to Peru and Brazil and is disjunct in 
the Dominican Republic. 

Manihot brachyloba is recognized by its usually 
vining habit, minute puberulence, never having 
more than three major leaf lobes, short racemose 
inflorescences, and smooth fruit. The waxy surface 
on the leaf undersides is verrucose ( x 50). The 
leaves may appear to be trifoliolate, but the lobes 
are connected by tissue at the base and do not 
have petiolules. 

Manihot esculenta Crantz, Inst. Rei Herb. 1: 167. 
1766. Jatropha manihot L., Sp. PI. 1007. 1753. 



Jatropha dulcis J. Gmelin, Onom. Bot. 5: 7. 
1772. Manihot utilissima Pohl, PI. Bras. Icon. 
Descr. 1: 32, t. 24. 1827. M. dulcis (J. Gmelin) 
Pax, Pflanzenreich IV, 147, 44: 71. 1910. Fig- 
ure 1. 

REFERENCES D. J. Rogers & H. S. Fleming, 
Monograph of Manihot esculenta Crantz. Econ. 
Bot. 27: 1-1 14. 1973. M. A. El-Sharkawy, Drought- 
tolerant Cassava for Africa, Asia, and Latin Amer- 
ica. BioScience 43: 441^*51. 1993. 

Shrubs or slender treelets l-2.5(-4) m tall, leafy stems 
1.5-8 mm thick, glabrous or sparsely puberulent with 
thin whitish hairs 0.1-0.2 mm long, roots producing 
tubers; stipules 5-14 mm long, triangular to linear, ca- 
ducous. Leaves with petioles 4-18(-25) cm long, 0.8-2.5 
mm thick, often puberulent near apex and base, often 
bent near apex and base, tissue of blade often united 
across apex of petiole (subpeltate); leaf blades with 3, 5, 
7(-l 1) lobes separated by deep sinuses, middle lobes 6- 
1 7(-22) cm long, 1-6 cm wide, narrowly elliptic, elliptic- 
obovate to oblanceolate or linear-oblong, apex acumi- 
nate, margins entire or slightly sinuate, gradually nar- 
rowed to base of sinuses, united basal part of blade 5- 
15 mm long, drying membranaceous to thin-charta- 
ceous, glabrous or less often minutely puberulent, usually 
glaucous beneath, 2 veins 5-1 I/side of the midvein. 
Inflorescences terminal or axillary, 2-10 cm long, pa- 
niculate, glabrous, bracts and bracteoles 1-3 mm long, 
linear, caducous, flowers on prominent pedicels. Male 
flowers yellowish, calyx 5-13 mm long, lobes 2-7 mm 
long, glabrous externally, disk 1 0-lobed; stamens usually 
10 in 2 series, filaments arising from between the lobes, 
anthers 1.5-2.5 mm long. Female flowers reddish green 
or purplish, calyx 10-12 mm long, 3-4 mm wide, gla- 
brous externally but puberulent along the inner edges, 
disk 2.5-3.5 mm wide; ovary 3-4 mm long, 2-3 mm 
diam., with 6 longitudinal ridges, styles 2 mm long, style 
branches 3 mm wide. Fruits 12-17 mm long, oblong- 
subglobose, usually with a rugose surface and 6 longi- 
tudinal fleshy ridges or wings; seeds 7-11 mm long, 4.5- 
7.5 mm wide, 4-5.5 mm thick, oblong with prominent 
lateral margins, caruncle 2-3.5 mm wide. 

Plants of open sites (often cultivated) or sec- 
ondary growth in both deciduous and evergreen 
areas, 0-1 500 m elevation. Flowering primarily in 
July-February. The species may have originated 
in Mexico and northern Central America but is 
now grown throughout the tropics. 

Manihot esculenta is recognized by its palmately 
lobed leaves with deep narrow sinuses, shorter in- 
florescences, ovary with fleshy longitudinal ridges 
or wings, and verrucose fruits. The vegetative parts 
contain cyanogenic glycosides that readily break 
down to prussic acid (HCN) and give a charac- 
teristic odor. This species is one of the world's 
most important food plants, with over 200 vari- 
eties cultivated for the tubers that are a very im- 



BURGER & HUFT: FLORA COSTARICENSIS 



135 



portant source of starch in many lowland tropical 
regions. These tubers can be left in the ground with 
little deterioration, avoiding storage problems. The 
plants are easily grown from stem cuttings, are 
highly productive, and have few insect pests. Some 
varieties of M. esculenta produce no flowers. Va- 
rieties with poisonous tubers are called "bitter" 
and those without poison "sweet." Standley (1937) 
listed the following indigenous names under M. 
dulcis: an (Bribri), unkah (Brunka), shku (Cabe- 
cara),and ik (Terraba). For M. esculenta, he listed 
ali and ili (Bribri), ungcah (Boruca), shko (Cabe- 
cara), shku (Estrella), iya (Guatuso), li (Talaman- 
ca), crosho (Terraba), and tatzica (Tucurrique). The 
species is called yuca, yuca amarga (Spanish), 
mandioca (Portugese), manioc (French), and "cas- 
sava" and "tapioca" (English). 

Manihot glaziovii Mull. Arg. in Mart., Fl. Bras. 
11 (2): 446. 1874. 

Trees 4-10 m tall, leafy stems 2-5 mm thick, glabrous, 
with copious latex; stipules 4-8 mm long, 1-2.2 mm 
wide at base, glabrous, caducous. Leaves peltate or sub- 
peltate, petioles (3-)8-20(-45) cm long, 0.8-2.4 mm thick, 
glabrous, with a narrowed area at the base when dried, 
attached (2-)5-30 mm from leaf edge; leaf blades 7-15 
cm long, 8-17 cm wide, deeply 3- (5-)lobed with sinuses 
3-9(-l 5) cm deep, middle lobe usually obovate, apices 
acute to rounded, margins entire, base truncated or sub- 
cordate, glabrous, venation palmate with 3 or 5 major 
veins. Inflorescences terminal or pseudoaxillary, 2-5/ 
node, 5-1 3 cm long, glabrous, 3 and 9 flowers with sepals 
ca. 15 mm long. 

Manihot glaziovii is a native of easternmost Bra- 
zil and has been cultivated as an ornamental in 
Central America. This species is also used for the 
production of latex (Ceara rubber), oil from the 
seeds; the leaves are eaten as a vegetable in Zaire. 
The deeply lobed peltate leaves with entire mar- 
gins are distinctive. 



M argaritaria Linnaeus films 

REFERENCE G. L. Webster, A revision ofAfar- 
garitaria (Euphorbiaceae). J. Arnold Arbor. 60: 
403-444. 1979. 

Shrubs or small trees, dioecious, branches usually dis- 
tichous, hairs simple, lenticels prominent; stipules entire 
or denticulate, caducous or persistent. Leaves alternate, 
simple, usually deciduous, petiolate, margins entire, pin- 
nately veined. Inflorescences usually appearing with the 
new flush of leaves, axillary, of solitary, paired or fas- 
ciculate flowers, usually at proximal nodes on new lateral 



shoots or in axils of distal leafy branchlets, flowers sub- 
tended by small bracts, pedicellate. Male flowers small 
and inconspicuous, sepals 4, united at base, unequal and 
biseriate, imbricate in bud, petals absent, disk annular, 
flat or slightly lobed; stamens 4, filaments usually free, 
anthers dehiscing longitudinally and extrorse; pistillode 
absent. Female flowers with 4 sepals united at the base, 
petals absent, disk annular, staminodes absent; ovary 
with 4-5 (2-3, 6) locules, styles 4-5 (2-3, 6), style branch- 
es bifid distally, ovules 2/locule. Fruits capsular, break- 
ing apart irregularly into 4-5 (2-3, 6) thin-walled 2-seeded 
cocci, green exocarp usually separating from the thin 
papery endocarp; seeds 2/locule, outer coat (exotesta) 
becoming fleshy and bluish when fully ripe, inner coat 
(endotesta) hard and woody (achene-like), ecarunculate, 
endosperm copious, whitish, cotyledons thin and flat. 

A genus of 14 species widely distributed in the 
moist tropics, except in the Pacific islands. Some 
taxonomists considered it to be a section of Phyl- 
lanthus, but Webster (see reference above) consid- 
ers it to be more closely related to Flueggea. The 
seeds have a fleshy exotesta and thin bony endo- 
testa, unlike other genera of Phyllantheae. Only 
the following species is found in Central America. 



Margaritaria nobilis L. f, Suppl. PI. Syst. Veg. 
428. 1781. Cicca antillana Juss., Tent. Euphorb. 
108, t. 4, f. 13B. 1824. Phyllanthus antillanw 
(Juss.) Miill-Arg., Linnaea 32: 51. 1863. P. no- 
bilis (L.f.) Mull- Arg., in DC., Prodr. 15 (2): 414. 
1866. P. nobilis var. hypomalacus Standl., Car- 
negie Inst. Wash. Publ. 461: 68. 1935. Figure 
25. 

Shrubs or small trees, 2-10(-20) m tall, dioecious, 
leafy stems 1-3 mm thick, glabrous or minutely (0.1- 
0.3 mm) puberulent but glabrescent, terete, with con- 
spicuous lenticels 0.4-0.8 mm long; stipules 2-4.5 mm 
long, 0.4-1.2 mm wide at base, narrowly triangular to 
subulate, acute, glabrous, usually persisting. Leaves de- 
ciduous, petioles 1.4-6(-10) mm long, ca. 1 mm thick, 
with thin lateral margins continuous with the lamina 
base, without glands; leaf blades 4-14(-18) cm long, 2- 
4.5(-6) cm wide, elliptic or oblong-elliptic to ovate or 
ovate-lanceolate, gradually tapering to an acute or acu- 
minate apex, acute to cuneate at the base, slightly de- 
current on the petiole, drying chartaceous, glabrous above, 
glabrous or with short (0.2-0.4 mm) thin hairs on the 
veins beneath, 2 veins 7- 11 /side. Inflorescences (see 
genus description), usually in anthesis when the leaves 
are deciduous and just as the new leaves begin to expand, 
pedicels unarticulated; 6 flowers 1-5 arising from small 
bracteate buds, pedicels 3-8 mm long, ca. 0. 1 mm thick 
(dried); 9 pedicels 6-10 mm long (to 15 mm in fruit), 
0.3-0.6 mm thick. Male flower buds 0.7-1 .3 mm diam., 
glabrous, perianth 2-3 mm wide at anthesis, sepals 0.6- 
1.5 mm long, disk annular, flat or slightly lobed, 1.4-3 
mm diameter; filaments 1-1.8 mm long, anthers 0.5-0.8 
mm long. Female flowers with sepals 1 .3-2.2 mm long, 
1.3-2.5 mm wide, obtuse, glabrous; ovary 1-1.8 mm 



136 



FIELDIANA: BOTANY 



long, 1.5-2 mm diam., glabrous, locules 4-5 (3, 6), style 
column 0.3-1 mm long, style branches usually 4, 1-1.5 
mm long, recurved, bifid in distal half. Fruits 7-8 mm 
long, 9-12 mm broad, rounded-oblate with 4-5 (rarely 
3 or 6) shallow longitudinal sulci, bright green, glabrous; 
seeds covered at maturity by a dark bluish fleshy coat, 
interior "achene" 3-5 mm long, 2.2-3.8 mm wide, 2- 
2.5 mm thick, with 2 flattened lateral sides, acute adaxial 
edge and rounded abaxial surface, smooth and yellowish 
(adjacent seeds sometimes coherent). 

Plants of both seasonally deciduous and very 
wet evergreen lowland rain forest formations, 0- 
1 100 m elevation. Flowering mostly in late May- 
September; fruiting in June-October. Flowering in 
Guanacaste usually occurs over a 3-day period 
about 2 weeks after the rainy season begins (Opler 
et al., 1976). Leaf fall occurs late in the dry season 
on Barro Colorado Island (Croat, 1978). The spe- 
cies ranges from Mexico and Cuba to Peru and 
Brazil. 

Margaritaria nobilis (formerly Phyllanthus no- 
bilis) is recognized by the clearly deciduous habit 
(there are no thick stems with leaves), small ax- 
illary unisexual (dioecious) flowers on slender ped- 
icels along distal stems, the minute 3 flowers, the 
rounded fruits with 4-5 (3, 6) 2-seeded cocci that 
break up irregularly, and the achene-like seeds 
covered with a thin fleshy bluish layer. A vege- 
tative distinction is that the petiole margins usu- 
ally merge with translucent tissue of the decurrent 
leaf edge at the base of the blade. In Costa Rica, 
the collections come primarily from lowland 
Guanacaste Province and from the Caribbean low- 
lands. Specimens from evergreen forests tend to 
have more elliptic leaves with a great number of 
2 veins. 



Omphalea Linnaeus 

Shrubs, trees, or lianas, monoecious, hairs simple, la- 
tex clear or reddish; stipules present, small. Leaves al- 
ternate, simple, petioles with 2 lateral glands at the apex, 
blades entire (in ours) to deeply lobed, often truncate to 
cordate at base, venation pinnate or palmate. Inflores- 
cences terminal (rarely axillary), solitary or several, uni- 
sexual or bisexual, spicate, racemose, paniculate with a 
central stem-like rachis and branched or unbranched 
lateral branches, bracts subtending the flower clusters 
(cymules) narrow and leaf-like, often biglandular, flowers 
small, the cymules entirely of 3 flowers or with a few 
central 2 flowers, pedicels short. Male flowers with 4-5 
decussate sepals, united at the base and imbricate in bud, 
petals absent, disk absent or small; stamens 2-3, fila- 
ments connate, connectives united into a fleshy structure 
bearing the 2-3 anthers at the periphery, anthers de- 
hiscing obliquely; pistillode absent. Female flowers with 
4-5 sepals united at the base, imbricate, petals absent, 



disk absent, staminodes absent; ovary (2-) 3-locular, styles 
connate into a column continuous with the ovary, 3-lobed 
at the tip or obscure, ovules 1/locule. Fruits fleshy and 
large, thick-walled and indehiscent or capsular with 3 
2-valved woody cocci; seeds subglobose, ecarunculate, 
endosperm present, cotyledons broad, cordate at base. 

A genus of 1 5 tropical species, with centers of 
diversity in the West Indies and Madagascar. This 
genus was studied by L. Gillespie (A revision and 
phylogenetic analysis of Omphalea (Euphorbi- 
aceae). Ph.D. thesis, University of California, Da- 
vis, 1988). 

Omphalea diandra L., Sp. PL ed. 2, 1377. 1763. 
O. diandra var. panamensis Klotzsch in See- 
mann, Bot. voy. Herald 101. 1853. Hebecocca 
panamensis Beurl., Svensk. Vet. Akad. Handl. 
1854 (Prim. Fl. Portob.) 146. 1856. O. pana- 
mensis (Beurl.) I. M. Johnston, Sargentia 8: 1 77. 
1949. Figure 31. 

Lianas to over 30 m high, stems to 20 cm diam., sap 
reddish to purplish, often with leafless distal stems (to 
60 cm long) twining around other stems, leafy stems 2.3- 
7 mm thick, densely yellowish brown pubescent with 
hairs 0.1-0.5 mm long; stipules ca. 2 mm long, 1 mm 
broad at the base, triangular and acute, densely hirsute. 
Leaves with petioles 1.2-6.5(-ll) cm long, 1-2.3 mm 
thick, densely hirsutulous, apex with 2 lateral flat round- 
ed (disk-like) glands 1-2 mm wide, pale green in life; 
leaf blades 6-18(-24) cm long, 3- 11 (-14) cm broad, 
broadly ovate to broadly ovate-elliptic, or ovate-oblong, 
apex obtuse to rounded or bluntly mucronate (short- 
acuminate), margin entire, base rounded and obtuse to 
subtruncate or slightly subcordate, drying stiffly char- 
taceous to subcoriaceous, grayish and glabrescent above, 
sparsely to densely pubescent beneath with hairs 0.2-0.4 
mm long, 2 veins 4-5/side, strongly ascending near the 
margin, 3 veins subparallel. Inflorescences 15-50 cm 
long, open-paniculate with alternate lateral branches to 
15(-25) cm long, densely puberulent with hairs 0.2-0.5 
mm long, flower clusters sessile or on short (2-7 mm) 
thick (1.3 mm) 3 branches, subtended by linear-lanceo- 
late bracts 3-24(-40) mm long, 1-3 mm broad, leaf-like 
(with petiole-like base, medial glands and distal narrow 
blade), cymules with all 3 flowers or with 1 central 2 and 
other 3 flowers (or solitary distal 9 flower), pedicels 0.5- 
2 mm long. Male flower buds 1 .5-2 mm diam., sparsely 
and minutely puberulent, sepals 1.5-2.5 mm long, the 2 
outer ca. 2 x 2 mm, rounded distally, green, the 2 inner 
reddish within and with thin margins, disk ca. 1.5 mm 
wide, flattened with a small central opening, reddish 
(Grayum 9820 F); anthers 2 (3), 0.6-0.8 mm long, con- 
nate with and a part of the periphery of the broadly 
rounded and distally flattened connective ca. 1.2 mm 
diam. Female flowers with calyx lobes 1-2 x 1.4 mm, 
triangular, pistil ca. 3 x 2 mm, pyriform or conical, 
densely velutinous, styles obscure, stigmas minute. Fruits 
8-12 cm diam., globose, fleshy but breaking up; seeds 
4-5 cm long, compressed rounded, brown or black, 
slightly rugose. 



BURGER & HUFT: FLORA COSTARICENSIS 



137 



Lianas of evergreen rain forest and partly de- 
ciduous forest formations in both the Caribbean 
and Pacific lowlands, 0-600 m elevation. Flow- 
ering and fruiting in December-April and August- 
September in Costa Rica. The species ranges from 
Honduras and the West Indies to Peru and Brazil. 

Omphalea diandra is recognized by its climbing 
habit, broadly ovate leaves with few major veins, 
petioles with two glands at the apex, large inflo- 
rescences with small flowers, narrow leaf-like 
bracts, and large round fruit. The androecium is 
quite unusual, resembling the peltate cap of a 
mushroom in outline and with a slender stalk. The 
two anthers occupy opposing sides on the periph- 
ery of the "cap." Some labels describe the plants 
as trees, but this may be in error. Large lianas are 
among the most poorly sampled members of the 
tropical flora, and it is likely that this species is 
more common than the few collections would in- 
dicate. Specimens from the Osa Peninsula have 
longer flora bracts than those from the Caribbean 
slope. 

Ophellantha spinosa Standl. is a species of 
northern Central America; Standley's citation for 
Costa Rica (Standley, 1938, p. 1557) appears to 
have been based on a misidentification. Webster 
(1994b, p. 107) merges Ophellantha with Acido- 
croton, and the species name is A. spinosus (Standl.) 
Webster. 



Pausandra Radlkofer 

Trees or shrubs, dioecious, stems with red or yellowish 
latex, stems with stellate or simple hairs attached at the 
center; stipules present, caducous. Leaves alternate, sim- 
ple, petioles thickened distally, blades serrate, with glands 
at the base, venation pinnate. Male inflorescences axil- 
lary, spiciform (rarely with lateral branches), flowers in 
sessile glomerules subtended by small eglandular bracts; 
<5 flowers subsessile, calyx lobes 5, imbricate in bud, pet- 
als 5 (6), connate near the base, villous within (adaxially), 
disk intrastaminal, cupulate, lobate, glabrous; stamens 
(3-)5-7, filaments free; anthers dehiscing longitudinally, 
introrse, connective not enlarged; pistillode absent. Fe- 
male inflorescences axillary, spiciform, bracts eglandular 
and sessile, subtending solitary sessile (short-pedicellate) 
flowers; 9 flowers with 5 imbricate sepals, petals 5, free, 
villous within, disc cupulate, entire or lobed, glabrous; 
ovary 3-locular, ovules 1/locule, styles 3, free, bifid. Fruits 
capsules splitting into 3 2-valved cocci; seeds smooth, 
carunculate, endosperm copious, embryo straight, cot- 
yledons palmately veined. 

A South American genus of approximately eight 
species, with one reaching as far north as Hon- 
duras. Note that while the bracts may be eglan- 



dular, the 2 inflorescences of our species may have 
glands present on the rachis near the sides of the 
floral bracts. 

Pausandra trianae Baillon, Adansonia 1 1 : 92. 1 873. 
Pogonophora trianae Mull. Arg., Flora 47: 434. 
1 864 (note that Baillon did not refer to Miiller's 
earlier name when he published this species). 
Pausandra extorris Standl., Trop. Woods. 17: 
24. Mar. 1929, and Publ. Field Columb. Mus., 
Bot. Ser. 4: 219. Oct. 1929. Clavija septentrion- 
alis L. O. Williams, Fieldiana Bot. 32: 205. 1970. 
Figure 13. 

Trees 3-30 m tall, trunks to over 30 cm thick, sap 
yellowish to red or brown, caustic, leafy stems 4.5-10 
mm thick, strigose with appressed straight or slightly 
crooked hairs ca. 0.3 mm long and attached at their 
center; stipules 5-6 mm long, 1-2 mm wide at base, 
triangular, thick, appressed to shoot apex, caducous. 
Leaves clustered near the ends of branchlets, petioles 8- 
60 mm long, 1 .8-5 mm thick, thickened near the apex, 
appressed strigose and glabrescent, with 2-4 cylindrical 
or crateriform glands 0.5-1.5 mm long near the apex, 
0.7-1 mm diam.; leaf blades 18-70 cm long, 8-22 cm 
wide, oblanceolate to narrowly oblanceolate or narrowly 
elliptic-obovate, apex abruptly narrowed or rounded, 
short-acuminate, margin with conspicuous rounded 
gland-tipped teeth 0.5-2.5 mm long, teeth 1-2/cm, base 
long-cuneate or long-attenuate, sparsely pubescent with 
appressed hairs 0.3-0.9 mm long above and below, gla- 
brescent between the veins, 2 veins 1 5-24/side, 3 veins 
subparallel. Male inflorescences 7-15 cm long, densely 
puberulent with appressed yellowish hairs ca. 0.2 mm 
long, rachis 1.5-2.5 mm thick, bracts inconspicuous, 
glomerules 3-6 mm distant along the rachis, with 5-12 
subsessile flowers; <5 flowers with calyx ca. 2 mm long, 
lobes 0.5-1 mm long, rounded distally, corolla 3-5 mm 
long, united at base, lobes broadly overlapping in bud, 
ca. 0.8-1.5 mm long, broadly rounded; disk ca. 0.8 x 
1.2 mm, spreading-cupulate, entire, stamens 6, filaments 
2.5-5 mm long, slender, glabrous, anthers 0.8-1.1 mm 
long. Female inflorescences 2-17 cm long, bracts ca. 1 
x 1.5 mm, broadly triangular and sessile, with cylin- 
drical glands 0.7 x 1.2 mm long often present near the 
sides, 0.5-1 mm diam.; 9 flowers with green sepals and 
yellow petals, cupular disc ca. 0.8 mm high, ovary 2-3 
mm long, 1.5-2 mm diam., ovoid-trigonous, sericeous, 
style branches ca. 1.8 mm long. Fruits ca. 13-14 mm 
long, strigose, green, woody wall ca. 1.2 mm thick, col- 
umella 8-9 mm long, ca. 3 mm wide at apex; seeds 9- 
1 1 mm long, 7.2-8.8 mm wide, 6-7 mm thick, rounded- 
oblong, dark, caruncle irregular and flattened. 

Plants of evergreen lowland rain forest forma- 
tions, 20-800 m elevation. Flowering occurs in 
December-June; fruiting in March-July. In Costa 
Rica, the species is usually found above 100 m 
elevation. The species ranged from Honduras to 
Amazonian Peru and Brazil. 

Pausandra trianae is recognized by its large ob- 



138 



FIELDIANA: BOTANY 



lanceolate serrate leaves clustered near the ends 
of unbranched branchlets, unusual pubescence, 
glands at the apex of the petiole, spiciform inflo- 
rescences with unisexual flowers, and broadly im- 
bricate perianth parts. The hairs appear to be sim- 
ple and appressed, but they are actually two- 
branched and attached at the center. 



Pedilanthus A. Poiteau, 
nomen conservandum 

REFERENCE R. Dressier, A monograph of the 
genus Pedilanthus (Euphorbiaceae). Contr. Gray 
Herb. 182: 1-188. 1957. 

Shrubs with woody or succulent greenish stems, usu- 
ally with few distal lateral branches, monoecious, sap 
usually whitish; stipules small, caducous. Leaves alter- 
nate, distichous, simple, sessile or petiolate, blades fleshy, 
margins entire. Inflorescences axillary or terminal cymes 
of few to many flower-like cyathia, bracts opposite, cy- 
athia pedunculate (appearing to be pedicellate). Cyathia 
bilaterally symmetrical, shoe-like in form, outer peri- 
anth-like involucre made up of 5 partly united bracts, 2 
adaxial bracts with or without glands along the adaxial 
edge, 2 lateral bracts asymmetric at the base and with 
glands along the abaxial margins, and an adaxial bract 
with glands on each edge, usually partly to entirely red- 
dish, bracteoles 0-many and filamentous within the cy- 
athium. Male flowers many, each <3 flower represented 
by an individual stipitate (pedicellate) stamen complete- 
ly lacking perianth, disk or pistillode; filament simple, 
anthers 2-lobed. Female flowers represented by a solitary 
stipitate (pedicellate) naked pistil within the cyathium, 
perianth and staminodes absent; ovary 3-locular, ovules 
1/locule, styles 3, united for most of their length, distally 
bifid. Fruits capsules or indehiscent, 3-lobed; seeds ovoid 
or rounded-angular, smooth or tuberculate, ecaruncu- 
late. 

A genus of 1 5 species centered in Mexico with 
1 species circum-Caribbean. The unusual flower- 
like cyathium is adapted for bird-pollination and 
probably derived from the more symmetrical cy- 
athium found in Euphorbia. The genus may not 
be native to Costa Rica; the few collections are 
probably escapes from cultivation. Pedilanthus 
millspaughii Pax & K. Hoffm. (Repert. Spe. Nov. 
Regni Veg. 19: 174, 1923) (based on Erode 2302 
from Miravalles, Costa Rica, destroyed at B) is a 
nomen dubium. 

Pedilanthus tithymaloides (L.) Poit., Ann. Mus. 
Natl. Hist. Nat. 19: 390. 1812. Euphorbia ti- 
thymaloides L., Sp. PI. 453. 1753. 

Shrubs with erect or scandent branches, 1-3 m long, 
distal stems often slightly zigzag, leafy stems 1.5-9 mm 



thick, at first with thin whitish hairs ca. 0.2 mm long, 
glabrescent, greenish and terete; stipules 0.3-1.2 mm 
d inm . , spur-like, caducous. Leaves subsessile or with pet- 
ioles to 6(-12) mm long, with lateral wings continuous 
with the blade; leaf blades 4-12(-16) cm long, 1.5-5(- 
10) cm wide, ovate-elliptic to ovate-orbicular or ovate- 
oblong, tapering gradually to an acute apex, margin en- 
tire or slightly undulate (dried), base obtuse, drying stiffly 
chartaceous to subcoriaceous, minutely puberulent or 
glabrous, venation obscure. Inflorescences terminal or 
axillary, 1-many cyathia in cymose groups, cyathia sub- 
tended by thin reddish bracts, peduncles (appearing as 
pedicels) 3-8 mm long, glabrous or puberulent. Cyathia 
7-1 5 mm long, 3-6 mm wide, slipper-shaped with curved 
basal spur or lobe to 4 mm long, glabrous or minutely 
puberulent externally, tube red above and green or yel- 
lowish beneath; $ flowers 20-34, stipes 7-14 mm long, 
filaments 2.5-3 mm long, anthers ca. 1.2 x 3 mm; 9 
flower (solitary naked pistil) on a stipe 4-14 mm long, 
ovary 1.5-2 mm long, styles 5-1 1 mm long, style branch- 
es 0.5-1 mm long. Fruits 5-6 mm diam., deeply 3-lobed 
in cross-section; seeds 3-4.5 mm long, 2.5-3.5 mm wide, 
ovoid to angled or subglobose. 

Pedilanthus tithymaloides is recognized by its 
arching greenish stems, semisucculent leaves, and 
unusual slipper-shaped cyathia that function as 
flowers. The species is probably an escape from 
cultivation in Costa Rica; it is often planted in 
gardens and hedges. Bitamo, bitamo real, pie de 
nino, pie de santo, and zapatilla are names used 
in Central America. 



Pera Mutis 

Trees or shrubs, dioecious (rarely monoecious), flat 
appressed lepidote hairs usually present on young stems 
and leaves (simple or stellate hairs may also be present); 
stipules small or absent. Leaves alternate (rarely oppo- 
site), simple, petiolate, eglandular, pinnately veined. Male 
inflorescences axillary, glomerules at leafless nodes or 
from leafless short-shoots, 1-15, pedunculate and at first 
resembling an individual flower bud with globose in- 
volucre enclosing 3-10 sessile flowers, involucre sub- 
tended by 1-2 bracts; $ flowers not all developing, calyx 
united and splitting into 2-4 acute lobes (or reduced), 
petals absent, disk absent; stamens 2-8, filaments short 
and free or longer and basally connate, anthers basifixed, 
dehiscing longitudinally; pistillode absent. Female inflo- 
rescences axillary, 1-2 or more/node, at first resembling 
a flower bud with a pedunculate globose involucre en- 
closing 2-5 pistils; 9 flowers lacking perianth, disc absent, 
staminodes absent; ovary short-stipitate, 3-locular, ovules 
1/locule, styles 3, short, connate at the base. Fruits cap- 
sules splitting into 3 2-valved woody cocci, columella 
not persisting; seeds ovoid to obovoid or oblong, com- 
pressed, smooth, lustrous, carunculate. 

A Neotropical genus of ca. 30 species, mostly 
Amazonian. Pera barbellata Standl., with smaller 
leaves and fruits, ranges from Veracruz, Mexico, 



BURGER & HUFT: FLORA COSTARICENSIS 



139 



to northern Honduras. The involucrate inflores- 
cences enclosing reduced <3 or 9 flowers may be 
mistaken for individual flowers. 

Pera arborea Mutis, Kongl. Vetensk. Akad. Nya. 
Handl. 5: 299, t. 8. 1784. Figure 26. 



translucent rays that are united for most of their 
length into a flat disk ( x 50). The fruits vary from 
being densely stellate tomentose to almost gla- 
brous. Further evaluation of the General Valley 
plants is needed to assess the significance of these 
differences. 



Trees 5-25 m tall, dioecious, trunks 12^0 cm diam., 
leafy stems 1-5 mm thick, sparsely to densely lepidote 
with flat rounded appressed brownish hairs 0.1-0.3 mm 
wide, mostly glabrescent; stipules absent. Leaves with 
petioles 4-14(-22) mm long, 0.8-1.7 mm thick, sulcate 
or slightly winged above (adaxially), lepidote; leaf blades 
(4_)5.5_14(_16) cm long, (1.5-)2.5-6(-7) cm wide, ellip- 
tic to elliptic-oblong or oblong, apex obtuse or cuspidate- 
acuminate, margin entire, base obtuse to cuneate, usually 
drying dark grayish or brown, glabrous or sparsely lep- 
idote above, with scattered lepidote hairs 0.1-0.2 mm 
wide beneath, 2 veins 7-12/side. Male inflorescences 
5-15, mostly at older leafless nodes or on leafless short- 
shoots, peduncles (appearing to be pedicels) 4-6 mm 
long, ca. 0.4 mm thick, lepidote, involucre at first glo- 
bose, 2-3 mm diam., subtended by 2 opposite unequal 
bracts 0.5-1.3 mm long, involucre (resembling a calyx) 
lepidote and splitting into usually 3 broad lobes; $ flowers 
difficult to distinguish, perianth ca. 1 mm long, with 
narrow lobes, stamens 4-6, filaments 0.7-1 mm long, 
anthers 0.8-1.1 mm long, ca. 0.7 mm wide. Female in- 
florescences axillary or at older leafless nodes, 2-5, pe- 
duncles 4-12 mm long, ca. 0.4 mm thick, lepidote, in- 
volucre breaking into usually 3 sepal-like parts 2-3 mm 
long, to 4 mm broad, lepidote externally, glabrous and 
drying black adaxially; 9 flowers usually 3, ovary ca. 2 
x 1 mm, narrowly ovoid, glabrous and drying black, 
style branches broad with erose margins. Fruits 12-14 
mm long, oblong and rounded or slightly trigonous in 
cross-section, surface glabrous or covered with scurfy 
hairs, fleshy and drying with wrinkled sharp-edged re- 
ticulated ridges, borne on stipes and peduncles ca. 4 + 
4 mm long, woody walls ca. 1 mm thick; seeds 6-7 mm 
long, 4.5-5.7 mm wide, 2.2-3 mm thick, ovoid-trian- 
gular with rounded proximal margin, dorsoventrally flat- 
tened, black and lustrous, the expanded thin yellowish 
caruncle partly covering the seed. 

Plants of evergreen wet forest formations, 5- 
1000 m elevation. Flowering primarily in August- 
January; fruiting in October and January-March. 
This species is uncommon in Costa Rica; it has 
been collected only at La Selva, in the General 
Valley, and near Golfito. The species ranges from 
Belize to Colombia. 

Pera arborea is recognized by the lepidote hairs 
on shoot apices and other parts, entire leaves lack- 
ing glands, groups of unisexual inflorescences that 
resemble globose flower buds, naked 9 flowers, 
fruits with wrinkled surfaces, and glossy black seeds 
partly covered by the expanded aril-like caruncle. 
The male inflorescences are easily misinterpreted 
as individual flowers. The hairs have a central 
(usually dark) attachment and many radiating 



Phyllanthus Linnaeus 

REFERENCES G. L. Webster, A monographic 
study of the West Indian species of Phyllanthus. 
J. Arnold Arbor. 37: 91-122, 217-268, 340-359. 
1956. 38: 51-80, 1 17-198, 295-373. 1957. 39: 49- 
100, 111-212, 1958. 

Herbs, shrubs, or trees, monoecious (dioecious), 
branches regular or specialized with axes of 2 kinds (per- 
sisting axes with spiral leaves and no flowers, and de- 
ciduous axes with distichous leaves often with axillary 
flowers), hairs simple or dendritic; stipules small, lateral, 
deciduous or persisting. Leaves alternate (rarely oppo- 
site), simple, short-petiolate, petioles without glands, 
blades usually thin-textured, margin entire, venation 
pinnate; scale-like cataphylls may be present. Inflores- 
cences usually axillary (cauliflorous or terminal), usually 
simple and unbranched, flowers solitary or in sessile fas- 
cicles (reduced cymes), <5 flowers on slender unarticulated 
pedicels, $ flowers subsessile or on unarticulate pedicels. 
Male flowers small, perianth free or united at base, sepals 
4-6 in 2 equal or subequal series, imbricate, petals ab- 
sent, extrastaminal disc usually present and lobed or 
divided; stamens 3-6 (2-15), filaments free or united, 
often forming a column, anthers dehiscing variously, 
thecae parallel or divergent; pistillode absent. Female 
flowers small, perianth free or united at the base, sepals 
5-6 in 2 series, equal or unequal, imbricate, petals and 
staminodes absent, disk usually saucer-shaped or divid- 
ed into segments or lobes (absent); ovary usually with 3 
locules (4, 5), ovules 2/locule, styles 3 (4), free or united, 
bifid or variously divided. Fruits usually capsules de- 
hiscing explosively into 2-valved cocci, less often in- 
dehiscent and baccate or drupaceous, columella persist- 
ing; seeds usually 2/locule, 3-angled or rounded and con- 
vex dorsally, sometimes with the 2 seeds of a locule 
dispersing as a single unit, ecarunculate, seed coat drying 
crustaceous, smooth or sculptured, endosperm cartilag- 
inous or fleshy. 

A diverse pantropical genus of 750-800 species, 
best represented in wet evergreen and seasonally 
moist areas. In South America, some species are 
used to make a fish poison, and there is a Salvinia- 
like aquatic (P. fluitans Mull. Arg.) unique in the 
family. Many of our species are weedy plants of 
open early secondary sites and are poorly repre- 
sented in herbaria. 

Phyllanthus is unusual in having many species 
in which the distal lateral stems are unbranched, 
deciduous, and with distichous small leaves. These 



140 



FIELDIANA: BOTANY 



branches resemble pinnate or bipinnate leaves. 
However, the leaflet-like leaves on these decidu- 
ous stems often subtend axillary flowers or fruits, 
distinguishing them from the leaflets of a truly 
compound leaf. The entire (usually small) leaves 
and small flowers in axillary clusters help make 
most of the species easy to recognize. Note that 
the unequal sepals in two whorls can be mistaken 
for two perianth whorls. The stamens are often 
united over much of their length, producing a sta- 



minal column supporting sessile and partly united 
anthers. The morphology of the pollen grain is 
important in determining the subgeneric place- 
ment of species. For a general review of the mor- 
phology of this genus, see L. Bancilhon, Contri- 
bution a Fetude taxonomique du genre Phyllan- 
thus (Euphorbiacees), Boissiera 18: 1-81, 1971. A 
closely-related ornamental with white-mottled 
leaves is Breynia disticha (q.v.). 



Key to the Species of Phyllanthus 

1 a. Leaves usually in a spiral and present on all distal stems, including the stems bearing the ultimate 

lateral leafy twigs; plants to 0.8 m tall [rarely collected in Costa Rica] 2 

Ib. Leaves usually distichous (in 2 opposing ranks) and restricted to the unbranched distal lateral 
stems which often resemble pinnate leaves, leaves usually absent on the stems that bear the distal 

lateral branches; plants 0. 140 m tall [various habitats] 4 

2a. Fruits 2.5-3 mm wide; seeds 1.4-1.6 mm long, smooth and lustrous; leaf blades usually 

narrowly elliptic and acute at the apex [moist habitats] P. hyssopifolioides 

2b. Fruits 1-2 mm wide; seeds 0.7-1.2 mm long, smooth but minutely rugulose; leaf blades 

usually oblong with bluntly obtuse or rounded apex 3 

3a. Female sepals usually 6 and narrowly oblong; distal stems usually terete and with or without 

winged ridges; 2 veins not or weakly loop-connected; stipules lacking basal lobes 

P. caroliniensis 

3b. Female sepals usually 5 and obovate; distal stems flattened and conspicuously winged; 2 
veins often loop-connected but difficult to see; stipules often with basal auriculate lobes . . 

P. compressus 

4a. Plants shrubs or trees, woody throughout, usually > 1 m tall 5 

4b. Plants herbs or subshrubs, if woody then only at the base, plants usually < 1 m tall 11 

5a. Largest leaf blades < 10 mm wide; seeds 1.7-2 mm long [leafy stems with persisting stipules 

2-4 mm long; plants to 5 m tall] P. valerii 

5b. Largest leaf blades > 10 mm wide; seeds 1.9-3.3 mm long 6 

6a. Leaves with 1 1-17 pairs of 2 veins [blades usually oblong-lanceolate in form, rare ^intro- 
duced) shrubs at ca. 1 800 m elevation] P. salviifolius 

6b. Leaves with 3-10 pairs of 2 veins 7 

7a. Stamens 4/flower; plants introduced and cultivated for their acidic fleshy fruits . P. acidus 
7b. Stamens 3/flower (or the 3 stamens united and with 6 thecae); plants indigenous, with dry 

fruits (fleshy in P. skutchii) 8 

8a. Leaf blades 5-11 cm long; fruits 7-9 mm diameter, globose, with a fleshy covering, seeds 

8/fruit, separate; trees 8-40 m tall [100-900 m elevation] P. skutchii 

8b. Leaf blades to 6 cm long; fruits less than 6 mm diam., dry, seeds 6/fruit or remaining as 

seed pairs and 3/fruit; shrubs or trees to 8 m tall 9 

9a. Seeds 2.6-3.3 mm long; 9 sepals 1.1-1.7 mm long; leaves elliptic to ovate-lanceolate, to 6 

cm long; 0-1 700 m elevation P. acuminatus 

9b. Seeds 1.9-2.5 mm long; 9 sepals 1.5-2.5 mm long; leaves broadly elliptic to ovate or sub- 
orbicular, to 4 cm long; 100-1400 m elevation 10 

lOa. Staminal column bearing 6 rounded thecae, the thecae from 3 slightly separated bases or 

from a single conical apex; leaves glabrous P. mocinianus 

lOb. Staminal column with a flat top and 6 narrowly oblong thecae along the edge; leaves glabrous 

or puberulent [Mexico to El Salvador; see discussion under P. mocinianus] . P. mcvaughii 

1 la. Fruits 3.5-4 mm wide, seeds 1 .7-2 mm long, minutely punctate or rugulose or sometimes appearing 



BURGER & HUFT: FLORA COSTARICENSIS 



141 



smooth with x 10 lens; stipules 0.5-2.7 mm long, distally filiform; 900-2500 m elevation [leaves 
to 1 6 mm long] P. niruri 

lib. Fruits 1.3-2.7 mm wide, seeds 0.8-1.4 mm long, transversely or longitudinally ridged or with 
longitudinal lines; stipules 0.4-2 mm long, not filiform distally; 0-1400 m elevation 12 

1 2a. Leaf blades usually minutely puberulent along the edges (glabrous on the broad flat surfaces), to 

25 mm long; seeds transversely ridged abaxially, often with rounded pits on the lateral sides . . . 

P. urinaria 

1 2b. Leaf blades glabrous throughout, to 1 2 mm long; seeds longitudinally ridged or with faint longi- 
tudinal lines, transverse ridges minute ( x 50) between the longitudinal ridges or lines, lateral walls 
often with concentric C-shaped ridges, never with pits 13 

1 3a. Female sepals narrow and acute at the apex; seeds with 4-7 prominent longitudinal ridges on the 
dorsal (abaxial) surface, 0.8-1.2 mm long; fascicles bisexual with 1 $ and 1 9 flower; moist to dry 
sites (not usually inundated) P. amarns 

1 3b. Female sepals broadly obtuse to rounded at the apex; seeds with 5-11 slightly elevated longitudinal 
ridges or lines on the abaxial surface, 0.9-1.4 mm long; fascicles unisexual, $ flowers 3-10/fascicle; 
plants often growing in moist soil or in standing water P. stipulatus 



Phyllanthus acidus (L.) Skeels, U.S. Dept. Agric. 
Bur. PL Ind. Bull. 148: 17. \909.Averrhoaacida 
L., Sp. PI. 428. 1753. Cicca disticha L., Mant. 
PL 1 24. 1 767. P. distichus (L.) Mull. Arg. in DC., 
Prodr. 15 (2): 4 13. 1866. 

Small trees or shrubs, 2-6(-8) m tall, leafy stems 0.7- 
2 mm thick, borne on woody branchlets 3-8 mm thick, 
glabrous; stipules 0.3-1 mm long, triangular, appressed, 
deciduous. Leaves distichous on slender stems, petioles 
1 .5-4 mm long, 0.4-1 . 1 mm thick, glabrous, drying dark; 
leaf blades 2.5-7 cm long, 1 .5-4.5 cm wide, ovate-elliptic 
to oblong-orbicular, acute to rounded at the apex, base 
obtuse or rounded-truncate, glabrous, varying from 
chartaceous and glaucous to thinner and greenish when 
dried, 2 veins 5-6/side. Inflorescences terminal or borne 
from older leafless nodes, <3 6-16 cm long, 9 to 3 cm 
long, racemose, glabrous, floral bracts 0.5-1 mm long; 6 
flower with 4 sepals and stamens. Fruits 6-10 mm long, 
7-20 mm diam., oblate, fleshy and with longitudinal 
riges, only 1 or 2 locules usually developing, edible. 

Phyllanthus acidus is recognized by the thicker 
branchlets bearing slender stems with short-peti- 
olate leaves (resembling a rachis with pinnate 
leaves), lack of pubescence, racemose 9 inflores- 
cences and fleshy fruits. The leaves are sometimes 
ovate-suborbicular. This native of South Asia has 
become naturalized in parts of seasonally dry 
northern Central America; it is often grown for the 
acidic fruits, which are cooked and used in pre- 
serves. It is called grosea and grosella in Central 
America. 



Phyllanthus acuminatus Vahl, Symb. 95. 1791. P. 
conami Sw., Prodr. 28. 1788, as to descrip. not 
as to type. P. brasiliensis sensu auct., non P. 
brasiliensis (Aubl.) Poir. (See Webster in J. Ar- 
nold Arbor. 38: 366, 1957). Figure 9. 



Shrubs or small trees 2-8 m tall, monoecious, with 
distal pinnatiform unbranched twigs 0.5-3.5 mm thick, 
minutely (0.05-0.2 mm) papillate-puberulent, greenish; 
stipules 0.4-1.3 mm long, deciduous. Leaves with peti- 
oles 1-3 mm long, 0.3-0.6 mm thick, minutely puber- 
ulent; leaf blades 1.6-5.8 cm long, 0.8-2.5 cm wide, 
ovate, ovate-elliptic, ovate-lanceolate or lanceolate (el- 
liptic), tapering abruptly or gradually to an acuminate 
(acute) apex, base obtuse to acute (rounded), drying thin- 
ly chartaceous, very minutely papillate-puberulent or 
scabridulous above, smooth and glabrous beneath, 2 
veins 3-5/side, arcuate-ascending. Inflorescences usually 
bisexual with fascicles of 5-25 6 flowers and 1 2 female 
flower, fascicles sometimes borne on short (1-2 mm) 
peduncles, the <5 flowers developing sequentially (often 
after anthesis of the 2), 6 pedicels 1.5-4 mm long, 2 
pedicels to 1 7 mm long in fruit. Male flowers 1-1.5 mm 
wide, sepals 6 in 2 unequal whorls, outer sepals ca. 1 x 
0.5 mm and narrowly oblong, inner sepals 0.9-1.2 mm 
long, rounded or obtuse, disk segments 3, reniform, ca. 
0.3 mm high; stamens 3, staminal column 0.1-0.3 mm 
long, ca. 0.7 mm wide at the flat 3-angled apex, anthers 
ca. 0.2 mm long, ovate, dehiscing laterally. Female flow- 
ers with 5 sepals in 2 unequal whorls, outer 1.1-1.5 mm 
long, 0.5-0.9 mm wide, ovate to obovate, inner sepals 
1.5-1.7 mm long, 1-1.3 mm wide, disk 3-lobed, ovary 
ca. 0.9 mm long, on a stipe 0.2-0.4 mm long, styles 3 
(4), 0.4-0.6 mm long. Fruits 3.7-4 mm long, 4-5 mm 
diam., with smooth rounded surfaces and 3 (4) sulci, 
columella 1.7-2.5 mm long, narrowed toward the apex; 
seeds often connivent in seed pairs, 2.6-3.3 mm long, 
2.5-2.9 mm wide, 1.8-2.4 mm thick, ovoid-subglobose, 
lustrous, usually brown, with a longitudinal sulcus when 
connate in a seed pair. 

Common plants of open secondary growth in 
both evergreen and deciduous forest formations, 
0-1 700 m elevation. Flowering primarily in May- 
July; fruiting primarily in June-August. The spe- 
cies ranges from Mexico and the West Indies to 
Argentina. 

Phyllanthus acuminatus is recognized by the 
consistently smaller leaf blades that are usually 



142 



FIELDIANA: BOTANY 



ovate to ovate-lanceolate with narrowed acumi- 
nate apices and the minutely papillate-puberulent 
(scabridulous) upper surfaces, which contrast with 
the glabrous lower (abaxial) surfaces. The seeds of 
the same locule tend to remain together as a seed 
pair. Despite its broad geographic range, this spe- 
cies has a sparse and weedy distribution in Costa 
Rica, suggesting that it may have been introduced. 
Chilillo and gallina are common names. 

Ph y I Ian thus amarus Schum. & Thonn., Beskr. 
Guin. PL 421. 1827; Kongl. Danske Vidensk 
Selsk. Skr. 4: 195. 1829. (See J. Arnold Arbor. 
37: 6-8, 1956, and 38: 313-315, 1957.) Fig- 
ure 8. 

Herbs or subshrubs with woody base, 1 5-90 cm tall, 
monoecious, usually with a single main stem and pin- 
natiform lateral branches 3-1 2 cm long with 1 0-36 leaves, 
internodes 1.5-6 mm long, leafy rachis 0.2-0.5 mm, 
glabrous, smooth and terete; stipules 0.5-1.3 mm long, 
linear-subulate, often unequal. Leaves with petioles 0.2- 
0.5(-0.7) mm long, 0.1-0.2 mm thick, glabrous, artic- 
ulate at base; leaf blades (2.5-)4-12 mm long, 2-5 mm 
wide, oblong to oblong-obovate, apex rounded to bluntly 
obtuse, base asymmetric, rounded or cuneate, drying 
thinly chartaceous, glabrous, 2 veins 3-5/side. Inflores- 
cences axillary, bisexual or of solitary 9 flowers, each 
fascicle usually with 1 9 and 1 $ flower, <5 pedicels 0.6- 
1 mm long, 9 pedicels to 2 mm long in fruit. Male flowers 
with 5 (6) sepals, 1.2-1.7 mm long, 0.3-0.7 mm wide; 
stamens 3 (2), stamina! column 0.2-0.3 mm long. Fe- 
male flowers with 5 sepals, 0.7-1 mm long, ca. 0.3 mm 
wide, narrowly oblong or oblong-obovate, rotate or be- 
coming reflexed; ovary smooth, styles 0.1-0.2 mm long. 
Fruits 1-1.3 mm long, 1.3-2 mm wide, smooth, colu- 
mella 0.7-0.9 mm long, 0.1-0.2 mm thick, cylindric; 
seeds 0.8-1 mm long, 0.5-0.7 mm wide, wedge-shaped 
(trigonous), yellowish, with 3-6 longitudinal ribs on the 
curved dorsal (abaxial) surface, inner lateral surfaces 
smooth or with concentric C-shaped ridges. 

Plants of open sites in evergreen and partly de- 
ciduous forest regions, 0-300 m elevation. Col- 
lected with flowers and fruit in February-Septem- 
ber. This species, probably native to the Americas, 
is now a pantropical weed. 

Phyllanthus amarus is distinguished by its low- 
elevation habitats (in Costa Rica), small oblong 
leaves, few-flowered bisexual fascicles, small se- 
pals subtending the yellowish fruit, and unusual 



seed surfaces. The longitudinal ridges on the dorsal 
surface of the seeds have very minute transverse 
pitting between them (x 50). Superficially, this 
species is easy to confuse with P. niruri, P. uri- 
naria, and P. stipulatus. 

Phyllanthus caroliniensis Walter, Fl. Carol. 228. 
1780. Figure 8. 

Herbs 4-^40(-60) cm tall, monoecious, usually with 1 
main stem and few to many erect lateral branches, both 
main and lateral stems with leaves, leafy stems 0.2-2 
mm thick, glabrous, terete or with slightly elevated lon- 
gitudinal ridges terminating at the petioles; stipules 0.5- 
l(-2) mm long, lanceolate-triangular, persisting. Leaves 
longer on the main stems than on the laterals, petioles 
0.4-1.3 mm long, ca. 0.2 mm thick, glabrous; leaf blades 
5-1 4(-l 8) mm long, 2-6(-8) mm wide, elliptic to broadly 
elliptic, elliptic-oblong or elliptic-obovate, apex obtuse 
to rounded, base obtuse to cuneate, drying membrana- 
ceous or thinly chartaceous, glabrous, 2 veins 3-5/side, 
usually readily visible. Inflorescences axillary, bisexual 
or unisexual, sessile, with 1-2 6 flowers and 1-2 9 flowers, 
9 pedicels to 1.2 mm long in fruit. Male flowers with 6 
(5) sepals 0.5-0.7 long, disk with 6 segments; stamens 
3, filaments free, short. Female flowers with usually 6 
sepals, 0.5-1.4 mm long, 0.1-0.3 mm wide, linear to 
narrowly oblong, style ca. 0.5 mm long. Fruits 0.9-1.3 
mm long, 1.5-2 mm wide, oblate, rounded and smooth, 
columella ca. 0.4 mm long; seeds 0.7-1 mm long, 0.4- 
0.7 mm wide, wedge-shaped, smooth, dull brown, mi- 
nutely rugulose (barely visible at x 10) with minute (0.02 
mm) dark lustrous spots in poorly defined longitudinal 
ranks on all surfaces. 

Plants of open sunny sites or in early secondary 
vegetation, 20-1400 m elevation. Probably flow- 
ering and fruiting primarily in the wet season or 
in wet sites. The species ranges from the eastern 
United States (Pennsylvania) to Argentina. 

Phyllanthus caroliniensis is recognized by its 
small weedy habit, small leaves on both 1 and 2 
axes, few-flowered fascicles of minute flowers, and 
small seeds with unusual surface ( x 50). The spe- 
cies has rarely been collected in Costa Rica. Com- 
pare the very similar P. compressus, which is also 
infrequently collected in Central America. Web- 
ster and Burch (1968) distinguish two subspecies 
of P. caroliniensis in Panama; the following key 
follows their discussion. 



1 a. Stems terete or slightly flattened distally but not distinctly winged; main stems usually with a number 
of lateral branches; plants of open weedy habitats ssp. caroliniensis 

Ib. Stems terete with sharp and narrowly winged ridges ca. 0.1 mm high distally; plants with no, few, 
or many lateral branches; plants of wet soils in open sites . . ssp. stenopterus (Mull Arg.) Webster 



BURGER & HUFT: FLORA COSTARICENSIS 



143 



Phyllanthus compressus H.B.K., Nov. gen. sp. 2: 
109. 1817. Figure 8. 

Herbs 6-30 cm tall, monoecious, often many-branched, 
all stems with leaves, leafy stems 0.5-1.5 mm thick, 
glabrous, distally flattened and with thin longitudinal 
ridges terminating beneath the petioles; stipules 1-2 mm 
long, narrowly triangular or subulate, often with basal 
auriculate lobes, persisting. Leaves with petioles to 1 mm 
long, glabrous; leaf blades 6-1 5 mm long, 3-8 mm wide, 
broadly elliptic to elliptic-oblong or oblong-obovate, apex 
broadly obtuse or rounded, drying chartaceous and often 
grayish, glabrous, 2 veins 3-5/side, often loop-con- 
nected near the margin but usually obscure. Inflores- 
cences axillary, usually bisexual fascicles with 1-2 <3 flow- 
ers and 1-2 9 flowers, glabrous, <5 pedicels to 1 mm long, 
2 pedicels to 1 mm long, often becoming reflexed. Male 
flowers with usually 5 calyx lobes 0.5-0.7 mm long, 0.5- 
0.7 mm wide, disk segments 5; stamens 3, filaments ca. 
0.5 mm long, partly united, anthers opening horizon- 
tally. Female flowers with 5 (6) calyx lobes 0.6-0.8 mm 
wide, obovate, disk entire; ovary smooth, styles ca. 0.4 
mm long. Fruits 1.7-2 mm wide, oblate, columella 0.5- 
0.7 mm long; seeds 0.9-1.2 mm long, wedge-shaped, 
brown. 

Weedy plants of open moist sites. The species 
has not been collected in Costa Rica but is known 
from many other areas of Central America. 

Phyllanthus compressus is very similar to P. car- 
oliniensis, which is also infrequently collected in 
Central America. The two species are separated 
by the characters used in the key to species. They 
share the unusual surface of the seeds (see under 
P. caroliniensis) as well as a very similar appear- 
ance. 



Phyllanthus hyssopifolioides H.B.K., Nov. gen. sp. 
2: 108. 1817. Figures. 

Herbs 12-40 cm tall, monoecious, with few lateral 
branches, all stems bearing leaves, 0.4-2 mm thick, gla- 
brous, slender longitudinal ridges ca. 0.2 mm high from 
the base of the petioles; stipules 0.5-1 .5 mm long. Leaves 
with petioles 0.2-0.8 mm long, 0.2-0.3 mm wide, gla- 
brous, base continuous with stem ridges; leaf blades 5- 
1 6 mm long, 1 .5-5 mm wide, elliptic-oblong to narrowly 
elliptic or narrowly ovate-elliptic, apex acute, base ob- 
tuse to acute, drying chartaceous and dark, glabrous, 2 
veins 2-4/side, usually obscure. Inflorescences axillary, 
unisexual, $ fascicles with few flowers, 2 flowers solitary, 
2 pedicels 1-2 mm long. Male flowers ca. 1.2 mm wide, 
sepals 5, 0.4-0.7 mm long, 0.4-0.7 mm wide, ovate to 
obovate; stamens 3, filaments ca. 0. 1 mm long, anthers 
0.1-0.2 mm wide. Female flowers with 6 sepals, 0.5-1 
mm long, ca. 0.4 mm wide, oblong to narrowly ovate, 
with pale margins; style branches ca. 0.2 mm long. Fruits 
1.8-2 mm long, 2.6-3 mm wide, oblate, rounded and 
smooth, yellowish; seeds 1.3-1.6 mm long, 1.1-1.2 mm 
wide, wedge-shaped, brown and lustrous, lateral faces 
often slightly concave. 



Plants of moist sites in lowland evergreen forest 
and seasonally wet savanna formations, 0400 m 
elevation. Flowering and fruiting in July-August. 
Locally common but rarely collected in Costa Rica 
and Panama, the species is disjunct in the Do- 
minican Republic, southern Central America, and 
northern South America. 

Phyllanthus hyssopifolioides is recognized by its 
short stature, preference for wet sites, narrow leaves 
usually tapering to an acute apex, few-flowered 
inflorescences, and dark lustrous seeds. We have 
seen only one Costa Rican collection (Zamora & 
Chacon 1389) from Refugio Carlo Negro, Alajue- 
la, where it was common at the edge of a seasonal 
lake. 

Phyllanthus leptobryosa J. D. Smith is Hyper- 
baena leptobryosa (J. D. Smith) Standl. of the 
Menispermaceae. 

Phyllanthus mocinianus Baill., Adansonia 1: 35. 
1 860. P. anisolobus Mull Arg. in DC., Prodr. 15 
(2): 382. 1866, ex char. P. pittieri Pax, Anal. 
Inst. Fis.-Geogr. Nac. Costa Rica 9: 195. 1898; 
and in Pittier, Prim. Fl. Costar. 2 (5): 327. 1900. 
Figure 9. 

Shrubs or small trees l-4(-8) m tall, monoecious, de- 
ciduous leafy branches to 55 cm long, appearing bipin- 
natifid with 5-12 alternating pinnatiform branchlets to 
30 cm long, leafy stems 0.3-3 mm thick, glabrous, with 
2 longitudinal ridges in early stages, terete; stipules 0.5- 
1.3 mm long, triangular, thin, persisting. Leaves with 
petioles 2-3 mm long, 0.2-0.4 mm thick, glabrous; leaf 
blades 1 1-40 mm long, 9-28 mm wide, broadly ovate 
to broadly elliptic or suborbicular, obtuse to rounded at 
the apex, base obtuse to rounded and subtruncate, drying 
grayish green, membranaceous or thin-chartaceous, gla- 
brous, 2 veins 4-7/side. Inflorescences axillary, usually 
fasciculate with 1-12 <5 flowers and 1 2 flower or with 
solitary 2 flowers, $ pedicels 3-10 mm long, filiform, 2 
pedicels 6-13 mm long. Male flowers whitish with green 
center, sepals 6 (5), 1.2-2.5 mm long, outer 0.7-0.8 mm 
wide, inner sepals 1-1.5 mm wide, disk ca. 1 mm wide, 
of 3 (6) large rounded parts; stamens 3, united into a 
column 0.4-1 mm long, apex of the column and anthers 
0.5-1 mm wide, anthers 0.3-0.4 mm long, thecae sep- 
arate. Female flowers 1 .8-2.5 mm wide, sepals 6, slightly 
larger than the <3, disk usually confluent to form a 3-lobed 
cup 0.5 mm high; ovary 0.9-1.7 mm long, 1-1.6 mm 
diam., smooth, style column 0-0.4 mm long, branches 
ca. 0.5 mm long, held horizontally. Fruits 2.5-3 mm 
long, 3-4.5 mm wide, oblate, columella 1.3-1.7 mm 
long; seeds 1.9-2.3 mm long, 1.3-1.7 mm wide, seed 
pairs ca. 2 mm wide, surfaces pale or dark brown with 
longitudinal ridges or smooth. 

Plants of evergreen and partly deciduous forest 
areas (often found along streams), 100-1300 m 
elevation (20-2100 m in Mexico and Guatemala). 



144 



FIELDIANA: BOTANY 



Flowering in April-August; fruiting in July-Oc- 
tober. The species (in a wide sense) ranges from 
Mexico to Peru. 

Phyllanthus mocinianus is recognized by the 
small rounded glabrous leaves, seeds often re- 
maining as seed pairs, and whitish <3 flowers with 
completely united filaments. Leaf blades vary from 
small (ca. 1 2 mm) ovate-orbicular to longer (3-4 
cm) ovate-elliptic in different plants. The anthers 
are unusual because the thecae are divergent and 
form six peripheral rounded lobes on the apically 
flattened staminal column. This species has the 
stamens more closely connate than does P. mi- 
crandus Mull. Arg. of northern South America. 
Specimens earlier determined as P. micrandrus in 
Mexico and Central America are this species or 
Phyllanthus mcvaughii Webster (southern Mexico 
to El Salvador). That species is virtually identical 
in appearance to the material placed here; how- 
ever, P. mcvaughii has six narrowly oblong thecae 
peripheral on the margins of the flat- topped edges 
of the umbrella-like androecium and appears to 
grow only at higher elevations (see Brittonia 18: 
336-342, 1966). It is possible, as a reviewer has 
suggested, that we are incorrect in submerging P. 
anisolobus under P. mocinianus and that the lower 
right section of Figure 9 is characteristic of P. an- 
isolobus (including P. pittieri). 



Phyllanthus niruri L., Sp. PL, 981. 1753. P. lath- 
yroides H.B.K., Nov. gen. sp. 2: 1 10. 1817. Fig- 
ure 8. 

Herbs or subshrubs with woody base, 10-1 20 cm tall, 
monoecious, usually with a single main stem and slender 
pinnatiform lateral branches 3-12 cm long with 16-36 
leaves and internodes 3-6 mm long, leafy rachis 0.3-0.6 
mm thick, glabrous; stipules 0.5-2.7 mm long, linear- 
subulate to filiform, often unequal, persisting. Leaves 
with petioles 0.2-0.5 mm long, ca. 0.2 mm thick, gla- 
brous; leaf blades (4-)5-12(-16) mm long, (1.5-)2.5-5(- 
8) mm wide, oblong or elliptic-oblong (rarely obovate, 
elliptic), apex broadly obtuse or rounded, often apiculate 
at the tip, base broadly cuneate or obtuse and slightly 
unequal, drying thinly chartaceous, glabrous above and 
below, 2 veins 4-7/side, ascending along the margin to 
form a submarginal vein. Inflorescences axillary, uni- 
sexual, glabrous, proximal nodes with 3-5(-7) $ flowers, 
distal nodes with solitary 9 flowers, <3 pedicels 1-2 mm 
long, 9 pedicels to 6 mm long in fruit. Male flower buds 
0.7-1 mm diam., to 3 mm wide at anthesis, sepals 5 (6), 
free or connate to 50%, lobes 0.5-1.5 mm long, disk ca. 
0.8 mm wide, with 5 rounded parts; stamens 3, filaments 
free or united, 0.4-1 mm long, anthers 0.2 mm long. 
Female flowers with 5 sepals, enlarging in fruit to 2.5-3 
mm long, 1-2 mm wide, yellowish or marked with red; 
ovary smooth, styles 0.5-0.6 mm long, bifid in the distal 
0.2-0.3 mm. Fruits 2.5-3 mm long, 3-4 mm wide, ob- 



late, surfaces smooth, yellowish, columella 0.5-1.2 mm 
long, narrowly conical; seeds 1.7-2 mm long, 1.1-1.3 
mm wide, wedge-shaped (trigonous), surface minutely 
rugulose or punctate with minute rounded projections 
in longitudinal ranks ( x 50). 

Plants of open sites in lower montane evergreen 
forest areas, 1000-2500 m elevation. Flowering 
and fruiting throughout the year. The species rang- 
es from Texas to Argentina. 

Phyllanthus niruri is distinguished by its mon- 
tane habitats, persisting filiform stipules, small ob- 
long glabrous leaves, few- flowered $ fascicles, con- 
spicuous sepals subtending the fruit, and larger 
darkly colored seeds with unusual surface. The 
secondary veins are loop-connected near the mar- 
gin, but this is often difficult to see. These char- 
acteristics help to distinguish this species from the 
superficially rather similar P. amarus, P. stipularis, 
and P. urinaria. 



Phyllanthus salviifolius H.B.K., Nov. gen. sp. 2: 
117, pis. 107, 108. 1817. 

Shrubs or small trees 3-5(-8) m tall, monoecious, leafy 
stems 0.7-6 mm thick, usually densely puberulent with 
short (0.2 mm) multicellular hairs (rarely subglabrous); 
stipules 4-7 mm long, 0.3-1.5 mm wide, linear to lan- 
ceolate, persisting. Leaves distichous on distal branchlets 
that may be deciduous (as in a pinnate leaf), petioles 2- 

4 mm long, usually puberulent; leaf blades 3-12 cm long, 
1.8-4 cm wide, oblong-lanceolate to narrowly ovate-tri- 
angular, tapering gradually to the acute apex, base round- 
ed to truncate or subcordate, drying chartaceous and 
brownish green, with short (0.2 mm) hairs on both sur- 
faces but the hairs denser and more curled beneath (rare- 
ly subglabrous), 2 veins 1 1-1 7/side, parallel and strong- 
ly ascending. Inflorescences bisexual or unisexual, of 5- 
1 5 flowers in dense axillary clusters, often small corymbs 
with short (0-4 mm) peduncles and short 2-5 mm few- 
branched rachis; pedicels of 6 flowers 3-5 mm long, gla- 
brous, pedicels of 9 flowers becoming 4 cm long in fruit, 
ca. 0.3 mm thick, glabrous. Male flowers greenish yellow 
or reddish, calyx in 2 subequal whorls of 3 each, 1.5-2 
mm long, oblong and rounded distally, disk a short cup; 
stamens 3-9, filaments united into a short column. Fe- 
male flowers reddish or purplish, sepals 6, subequal, 4- 

5 mm long, 2-2.8 mm wide, ovate-oblong, rounded at 
apex, disc forming a short cup; ovary ca. 1.3 x 2 mm, 
glabrous, styles ca. 3 mm long, united only near the base, 
stigmas ca. 0.5 mm long, twisted, red. Fruits 4-4.5 mm 
long, 5-6 mm wide, oblate to rounded-oblong, surfaces 
smooth, subtended by the persisting perianth; seeds 2.5- 
2.8 mm long, ca. 2 mm wide, wedge-shaped, with fine 
longitudinal ridges abaxially and concentric C-shaped 
ridges on the sides. 

Known only from the Cerros de Escazu, south 
of San Jose (G. Vargas 679 F, usj) in Costa Rica. 



BURGER & HUFT: FLORA COSTARICENSIS 



145 



The species grows from 1 800 to 3500 m elevation 
in the northern Andes, Venezuela, to Peru. 

Phyllanthus salviifolius is recognized by its short- 
petiolate leaves with usually lanceolate blades, 
many parallel ascending secondary veins, and ax- 
illary clusters of 9 or $ flowers. With only a single 
collection made in Central America, not far from 
a densely populated region, it seems likely that 
this species is a recent introduction. 

Phyllanthus skutchii Standl., Publ. Field Mus. Nat. 
Hist., Hot. Ser. 22: 347. 1940. Figure 25. 

Trees 8-45 m tall, trunks to 1 m diam., bark lightly 
fissured to deeply furrowed and rough brown, wood pale 
and soft, monoecious, leafy stems 0.7-3 mm thick, gla- 
brous, terete; stipules 0.5-2 mm long, narrowly trian- 
gular, acute to acuminate, glabrous or minutely puber- 
ulent, persisting. Leaves distichous, petioles 2-6 mm long, 
0.7-1.2 mm thick, glabrous, drying dark and wrinkled; 
leaf blades 5-1 1 cm long, 1.74 cm wide, ovate-elliptic 
to oblong-lanceolate or narrowly elliptic-oblong, apex 
acuminate with narrow tip, margin slightly thickened at 
the petiole, base obtuse or slightly rounded, drying char- 
taceous, glabrous or with few minute hairs near the base 
beneath, 2 veins 6-10/side, ascending. Inflorescences 
axillary, glabrous, unisexual, proximal fascicles of 15- 
30 6 flowers, distal fascicles with 1-9 9 flowers, each <? 
flower subtended by a series of imbricate bracts, pedun- 
cles 1-3 mm long, $ pedicels to 5 mm long, fruiting 
pedicels 3-7 mm long. Male flower buds ca. 1.5 mm 
diam., sepals usually 6, outer ca. 1.7 x l mm, inner ca. 
1.2 x 0.7 mm, broadly obovate to oblong, rounded dis- 
tally, glabrous, disc with ca. 1 2 peripheral lobes; stamens 
3, free, filaments ca. 0.4 mm long, thick, anthers ca. 0.4 
mm wide, dehiscing horizontally. Female flowers with 6 
(7) unequal sepals, 2-2.8 mm long in fruit, 1-2.7 mm 
wide, narrowly oblong to obovate, disc flat or a thin cup 
with rounded lobes ca. 0.5 mm long, ovary 4- (S-)locular. 
Fruits 7-9 mm diam., globose, with a thin fleshy smooth 
covering, persisting style base ca. 0.5 mm high, walls of 
the cocci thin; seeds ca. 7 x 3.5 mm, wedge-shaped, 
trigonous in cross-section. 

Rarely collected trees of evergreen forest for- 
mations, 20-900 m elevation. Flowering in Jan- 
uary and May; fruiting material was collected in 
May-June and December. This endemic species 
is known only from the General Valley (Skutch 
4325 the type, 5427, 5491), near Golfito (Aguilar 
746, Schmidt 594), and in the Braulio Carillo Na- 
tional Park (Hammel et al. 17820). 

Phyllanthus skutchii is recognized by its tall stat- 
ure and normal-sized foliage (unusual in Phyllan- 
thus), lack of pubescence, usually unisexual fas- 
cicles, six-parted perianth, free stamens, four-loc- 
ular ovary, and eight-seeded fleshy fruits. The 
leaves resemble some other genera of Euphorbi- 
aceae (e.g., Margaritaria) and some Flacourti- 



aceae. This species is another example of Alex- 
ander Skutch's important contribution to our 
knowledge of Costa Rica's flora. 

Phyllanthus stipulates (Raf.) Webster, Contr. Gray 
Herb. 176: 13. 1955. Moeroris stipulata Raf., 
Sylva Tellur. 91. 1838. Figure 8. 

Herbs or slender subshrubs 10-90 cm (to 2 m?) tall, 
monoecious, often with 1 main stem and alternate lateral 
pinnatiform leafy stems 2-7 cm long with 10-30 leaves, 
0.2-0.4 mm thick, glabrous; stipules 0.5-0.8 mm long, 
linear to lanceolate, persisting. Leaves closely (0.7-3 mm) 
spaced, petioles 0.3-0.6 mm long, ca 0.2 mm thick, gla- 
brous; leaf blades 2.5-7(-8) mm long, 0.8-3(-4) mm 
wide, narrowly oblong to narrowly elliptic-oblong, apex 
bluntly obtuse to slightly rounded, base cuneate to 
rounded and somewhat unequal, drying thinly charta- 
ceous, grayish beneath, glabrous, smooth or slightly sca- 
bridulous, 2 veins 3-6/side, usually obscure. Inflores- 
cences axillary, unisexual, proximal nodes with 3-10 <5 
flowers, distal nodes with solitary 2 flowers, 6 pedicels 
0.3-0.7 mm long, 9 pedicels becoming 2 mm long in 
fruit. Male flowers with 5 sepals, 0.5-1 mm long, disk 
entire or lobed; stamens 3 (2), united into a column 0.2- 
0.3 mm long, anthers dehiscing horizontally. Female 
flowers with 5 sepals, 0.7-1.8 mm long, 0.4-1.2 mm 
wide, usually obovate and bluntly obtuse to rounded at 
the apex; styles 0.2-0.3 mm long, free. Fruits 1.2-2 mm 
long, 2-2.7 mm wide, surfaces rounded, columella 0.7- 
0.8 mm long, ca. 0.2 mm thick; seeds 0.9-0. 14 mm long, 
0.70.9 mm wide, wedge-shaped (trigonous), abaxial 
surface with 5-1 1 thin longitudinal ridges or lines and 
many minute parallel transverse ridges ( x 50) between 
them. 

Plants of moist sites or growing in shallow water 
in evergreen forest areas, 0-1200 m elevation. 
Probably flowering and fruiting throughout the 
year. This species ranges widely through the Amer- 
ican tropics. 

Phyllanthus stipulatus is recognized by its pref- 
erence for wet sites, lack of pubescence, small ob- 
long leaves, solitary female flowers, and seeds with 
unusual abaxial surface. Plants growing in water 
often develop spongy (aerenchymatous) stems and 
roots. The stems are often reddish. Compare P. 
amarus with very similar seeds but few-flowered 
bisexual inflorescences. 

Phyllanthus urinaria L., Sp. PI. 982. 1753. Fig- 
ure 8. 

Herbs or subshrubs 10-90 cm high, erect or arching 
over, monoecious, usually with 1 main stem and shorter 
pinnatiform lateral stems with 20-35 leaves, leafy stems 
0.3-0.7 thick, minutely (0. 1-0.3 mm) ciliolate along the 
slender longitudinal ridges (glabrous); stipules 1-1.5 mm 
long, lanceolate to subulate, persisting (stipule-like struc- 
tures at base of leafy branchlets to 2 mm long). Leaves 



146 



FIELDIANA: BOTANY 



with petioles 0.3-0.5 mm long, ca. 0.3 mm thick, usually 
glabrous; leaf blades 4-14(-25) mm long, 1.5-5(-9) mm 
wide, narrowly oblong to narrowly oblong-obovate, apex 
obtuse to rounded-truncate, base often asymmetrical, 
rounded or slightly auriculate at the petiole, drying thin- 
chartaceous, grayish green to yellowish green, glabrous 
except for the minute (0.05-0.1 mm) hairs along the 
edge, 2 veins 3-5/side, ascending. Inflorescences axil- 
lary, sessile, unisexual, proximal nodes with solitary 2 
flowers, distal nodes with fascicles of 5-7 $ flowers, <5 
pedicels ca. 0.5 mm long, 2 pedicels 0-0.05 mm long. 
Male flowers with 6 sepals, less than 0.5 mm long, disk 
crenulate; stamens 3, united into a column, anthers de- 
hiscing vertically. Female flowers with 6 sepals, 0.5-1 
mm long, 0.2-0.4 mm wide; ovary 0.7-1 mm long, sub- 
globose, with scale-like processes on the surface, styles 
connate, bifid at apex. Fruits 1.3-1.7 mm long, 2.2-2.5 
mm wide, oblate and rounded with 3 or 6 sulci, columella 
0.7-1 mm long, darker at the acute apex; seeds 1.1-1.4 
mm long, 0.7-0.9 mm wide, wedge-shaped, dorsal sur- 
face with ca. 10 transverse ridges, often with 1-3 pits on 
the lateral side. 

Plants of open sunny sites in moist evergreen 
areas, 0-1400 m elevation. Fruiting throughout 
the year in Costa Rica. A native of tropical Asia 
now widely naturalized in the American tropics. 

Phyllanthus urinaria is recognized by its small 
oblong leaves usually with minute hairs along the 
margins and seeds with transverse ridges across 
the back. The leaves are reported to be "sensitive," 
folding up after contact. This species has been used 
as a medicinal herb and called chancapiedras (Bel- 
lo & Rojas 2302) and rinoncillo (Sanchez & Za- 
mora 150) in Costa Rica. 

Phyllanthus valerii Standl., Publ. Field Mus. Nat. 
Hist., Hot. Ser. 18: 619. 1937. Figure 9. 

Shrubs or small few-branched treelets 0.5-5 m tall, 
monoecious, with distal unbranched pinnatiform lateral 
stems 5-30 cm long and 10-40 leaves, leafy stems 0.4- 
2 mm thick, sparsely to densely minutely (0.05-0.2) pa- 
pillate-puberulent, terete; stipules 2-4 mm long, 0.3-0.5 
mm wide at the base, linear-lanceolate, persisting. Leaves 
with petioles 0.5-1.5 mm long, 0.3-0.4 mm thick, gla- 
brous or sparsely papillate puberulent; leaf blades 5-2 2(- 
30) mm long, 2.5-9(-12) mm wide, oblong-obovate to 
elliptic oblong or oblong, apex obtuse to rounded (acute), 
base obtuse and slightly assymmetric, drying charta- 
ceous, glabrous, 2 veins 4-8/side, ascending and often 
weakly connected near the margin. Inflorescences axil- 
lary, unisexual or bisexual, fascicles with 3-5 6 flowers 
or solitary 2 flower, glabrous, bracts stipule-like, 9 ped- 
icels to 3 mm long in fruit. Male flowers whitish, sepal 
lobes 5, 1-1.5 mm long, 1-1.5 mm wide, rounded dis- 
tally, disk with 5 stalked glands 0.5-0.6 mm long with 
stipes ca. 0.3 mm long; staminal column ca. 1.2 mm 
long, 0.7-0.8 mm wide at the apex with 2-3 sessile an- 
thers dehiscing horizontally. Female flowers with usually 
6 sepals, 0.8-1.5 mm long, 0.6-1.1 mm wide, oblong to 
narrowly ovate (enlarging slightly in fruit); ovary ca. 0.8 



mm diam., styles ca. 0.5 mm long. Fruits 1.7-2.2 mm 
long, 2.7-4 mm wide, oblate, rounded and slightly 
3-lobed, smooth, yellowish, columella 1.3-1.7 mm long, 
0.3-0.4 mm thick, narrowed distally; seeds 1.7-2 mm 
long, 1 .3-1 .4 mm wide, wedge-shaped with rounded edg- 
es, surface smooth (x 10) but with minute lustrous 
rounded punctations in poorly denned longitudinal rows 
(x 50). 

Plants of wet evergreen montane forest forma- 
tions along the central highlands, 1100-2100 m 
elevation. Probably fruiting throughout the year. 
The species is endemic to Costa Rica, ranging from 
the Cordillera de Tilaran eastward to the western 
slopes of the Cordillera de Talamanca (Tapanti). 

Phyllanthus valerii is recognized by its restricted 
montane habitat, leaves that are somewhat larger 
than most of our other species of Phyllanthus with 
narrowly oblong leaves, minute pubescence on leafy 
stems, slender persisting stipules, and few-flow- 
ered inflorescences. Characteristics of seed surface 
and flowers suggest a relationship with P. niruri. 



Plukenetia Linnaeus 

REFERENCE L. J. Gillespie, A synopsis of Neo- 
tropical Plukenetia (Euphorbiaceae) including two 
new species. Syst. Bot. 18: 575-592. 1993. 

Vines or lianas, young stems with short thin simple 
hairs; stipules small, deciduous. Leaves alternate, peti- 
olate, blades entire or minutely dentate, venation pinnate 
or palmate, sessile glands usually present near the petiole. 
Inflorescences terminal, leaf-opposed or axillary, nar- 
rowly paniculate to thyrsoid or racemose, bisexual or <3, 
2 flowers 1-2 and basal, 3 flowers in distal glomerules 
along an unbranched rachis, bracts small and without 
glands. Male flowers pedicellate, calyx divided into 3-5 
parts, petals absent, receptacle slightly to distinctly con- 
ical, interstaminal disk of segments or absent; stamens 
10-40, filaments free or united at base, anthers 4-thecous, 
connective apiculate; pistillode absent or minute. Female 
flowers pedicellate, calyx 4-parted, slightly imbricate, 
petals and disk absent, staminodes absent; ovary with 4 
locules, ovules 1/locule, styles connate for '/2 or more of 
their length, often thick, simple or obscurely bifid. Fruits 
capsules, cocci smooth to carinate or winged; seeds len- 
ticular to globose, smooth or ridged, ecarunculate, en- 
dosperm present, cotyledons ovate. 

A tropical genus of about 1 6 species, absent from 
Australia. The slender vining stems, gland-bearing 
denticulate leaves, minute $ flowers with many 
stamens, and unusual oblate four-lobed, four- 
seeded capsules help distinguish our material. The 
two species included here are uncommon in Cen- 
tral America. 



BURGER & HUFT: FLORA COSTARICENSIS 



147 



Key to the Species of Plukenetia 

la. Leaf blades mostly ovate with palmate or subpalmate venation, stipels (glands) present at apex of 
petiole; inflorescences usually terminal or leaf-opposed; capsules 25-35 mm wide . . . P. stipellata 

Ib. Leaf blades mostly oblong with pinnate venation, stipels or glands absent at apex of petiole; inflo- 
rescences axillary; capsules ca. 1 5 mm wide P. penninervia 



Plukenetia penninervia Mull Arg., Linnaea 34: 1 58. 
1864. P. angustifolia Standl., Publ. Field Col- 
umb. Mus., Bot. Ser. 4: 314. 1929. Figure 31. 

Vines, woody near the base, leafy twigs 0.8-3.5 mm 
thick, with minute (0.1-0.2 mm) thin erect hairs, soon 
glabrescent; stipules ca. 1 mm long. Leaves with petioles 
4-14 mm long, 0.9-1.6 mm thick, often thickened near 
the apex, minutely puberulent; leaf blades 6-16 cm long, 
2-6 cm wide, narrowly elliptic-oblong to oblong or ob- 
long-lanceolate, apex acute to acuminate (rounded and 
short-acuminate), margin minutely (0.2 mm) glandular 
denticulate, base rounded to obtuse, with flat elliptic 
glands or glandular thickenings near the petiole on the 
adaxial surface, drying chartaceous, greenish, 2 veins 6- 
10/side. Inflorescences axillary, bisexual or <5, 5-30 mm 
long, rachis unbranched and minutely puberulent, $ flow- 
er proximal and solitary, borne on slender pubescent 
pedicels 8-20 mm long, $ flowers with slender puberulent 
pedicels to 8 mm long. Male flowers with 3 sepals, 1- 
1.5 mm long, broadly elliptic or obovate; stamens ca. 
14-18, dimorphic, outer 4-5 stamens with filaments ca. 
0.2 mm long, inner 10-12 anthers sessile on the globose 
receptacle, anthers ca. 0.2 mm long. Female flowers with 
sepals 1-1.2 mm long, triangular, puberulent along the 
middle abaxially; ovary ca. 1.7 long, 2.5-3 mm diam., 
stylar column 1.6-2 mm long, ca. 0.8 mm thick. Fruits 
ca. 1 x 1.5 cm, oblate and prominently 4-lobed, tuber- 
culate around the middle; seeds ca. 5 mm long, 3-4 mm 
thick. 

Plants of evergreen lowland forest formations, 
0-600 m elevation. Known in Costa Rica from 
only a single collection near Golfito (Moreno et al. 
122 MO); flowering in January. The species ranges 
from southern Mexico to Venezuela and Peru. 

Plukenetia penninervia is recognized by its slen- 
der-stemmed vining habit, oblong pinnately veined 
leaf blades glandular at the base, small unbranched 
inflorescences, and four-lobed oblate fruits. 



Plukenetia stipellata L. J. Gillespie, Syst. Bot. 18: 
588. 1993. P. volubilis auct. non L. (for Central 
American material, see below). Figure 5. 

Slender herbaceous vines or lianas, monoecious, leafy 
stems 0.7-3 mm thick, minutely (0.1 mm) papillate- 
puberulent, glabrescent; stipules 0.5-1 mm long. Leaves 
with petioles 20-60(-80) mm long, 0.6-1.3 mm thick, 
minutely puberulent, sulcate above, often geniculate at 
the base, usually with 2 small (0.3-1 mm) glands at the 
adaxial apex; leaf blades 6-15 cm long, 3-13 cm wide, 



ovate to ovate-triangular, tapering gradually to the acu- 
minate or caudate-acuminate apex, tip 4-20 mm long, 
margin minutely (0.2 mm) serrulate, base broadly obtuse 
to truncate or cordate, basal sinus 0-2 cm deep, with 
narrow oblong glands 1-2.2 mm long along the proximal 
basal edge 2-5 mm from the petiole, drying membra- 
naceous to chartaceous, greenish, usually glabrous above, 
with minute (0.1 mm) hairs along the veins beneath, 
venation palmate or subpalmate, with 3 major veins, 2 
veins 2-4/side of the midvein. Inflorescences terminal 
on short-shoots (axillary), solitary, 2.5-10 cm long, usu- 
ally bisexual with 1 proximal 2 flower and glomerules of 
$ flowers along a slender (0.5 mm) minutely puberulent 
unbranched rachis, $ pedicels 0.3-1 mm long, $ pedicels 
2-8 mm long (to 25 mm in fruit). Male flowers buds ca. 
1.5 mm diam., calyx lobes 5 (4), 1.8-3 mm long, tri- 
angular, stamens 25-40, filaments 1-1.2 mm long, an- 
thers 0.3-0.4 mm long, with a gland at the apex of the 
connective. Female flowers ca. 8 mm long, sepals 1-2 
mm long, 0.9-1 mm wide, narrowly triangular; ovary 
2-7 mm diam., stylar column 6-11 mm long, ca. 1.3 
mm diam., drying dark, glabrous, with 2 thick distal 
styles 1.3-2 mm long. Fruits 13-26 mm long, 22-35 mm 
wide, truncated at apex and base, with 4 prominent lat- 
eral lobes, surface smooth, columella 8-10 mm long, 6- 
8 mm wide at the apex; seeds 11-14 mm long, 9-12 mm 
wide, 5-6 mm thick, lenticular with an acute circum- 
ference, surface with raised ridges and minor reticula- 
tion. 



Plants of evergreen forest formation, 0-8 00(- 
1200) m elevation. Flowering and fruiting pri- 
marily in the wet season, June-November. The 
range of the species in Costa Rica is unusual: col- 
lections have been made only north of the Rio 
Pacuare in the Caribbean lowlands and from the 
Osa Peninsula area. The species is found in eastern 
and southern Mexico, Guatemala, and Nicaragua 
to Panama. 

Plukenetia stipellata is recognized by the slen- 
der-stemmed vining habit, ovate leaf blades with 
distinctive glands at the lamina base, slender in- 
florescences with unusual 9 flowers, and oblate 
prominently four-lobed fruits. The glabrous ovary 
with its thick stylar column may be mistaken for 
an immature corolla tube. Our material was for- 
merly considered part of P. volubilis, but Gillespie 
(reference above) notes that P. volubilis lacks the 
glands at the apex of the petiole and has fewer 
stamens (16-30), thicker filaments, and a longer 
stylar column, and the staminate sepals are con- 
sistently four. However, with possible interme- 



148 



FIELDIANA: BOTANY 



diate forms in Colombia and Venezuela, our ma- 
terial might also be interpreted as a subspecies of 
P. volubilis. 

Richer ia Yah 1 

REFERENCE R. Secco & G. L. Webster, Mar- 
eriais para a flora amazonica IX. Ensaio sobre a 
sistematica de genero Richeria. Bol. Mus. Para. 
Emilio Goeldi, Bot. 6: 141-158, 1990. 

Trees or shrubs, dioecious, glabrous or with simple 
hairs; stipules enclosing the shoot apex, caducous. Leaves 
alternate, petiolate, margins entire or crenulate distally, 
pinnately veined, sometimes with glands at the base of 
the blade. Male inflorescences axillary, spicate with ses- 
sile flowers or racemose with sessile flowers in pedun- 
culate glomerules, bracts subtending several small flow- 
ers; $ flowers with 3-5-lobed calyx, lobes imbricate in 
bud, petals absent, disk segments 3-5, interstaminal; sta- 
mens 3-6, filaments free, exserted, anthers versatile, 
oblong, dehiscing longitudinally, introrse or extrorse; 
pi s t i 1 lode minute. Female inflorescences axillary, solitary 
from the axil of a bract, shorter than the 6, racemose, 
flowers solitary and pedicellate; 2 flowers with 3-5-lobed 
calyx, lobes imbricate in bud, persisting in fruit, petals 
absent, disk cupulate or undulate, ovary 2- or 3-locular, 
glabrous or puberulent, ovules 2/locule, styles 2 or 3, 
short, thick, bifid at the tip. Fruits capsules but somewhat 
fleshy and dehiscing late, breaking into 2-valved cocci, 
1 -seeded, columella slender, dilated distally; seeds eca- 
runculate, outer testa fleshy, endosperm present, coy- 
tyledons broad, plane, basally cordate. 

A Neotropical genus of five species, one reach- 
ing Costa Rica. See Webster and Huft (1988) for 
a short discussion of relationships of the genus and 
differentiation of the species found in Panama. 
Despite the bicarpellate ovaries, we take a broad 
view and include all Costa Rican material under 
R. obovata (see below). 

Richeria obovata (Mull. Arg.) Pax & K. Hoffhi., 
Pflanzenreich IV. 147. XV (Heft 81): 29. 1922. 
Richeria grandis var. obovata Mull. Arg. in DC., 
Prodr. 15 (2): 468. 1866. Figure 28. 

Trees 9-30 m tall, trunks to 80 cm diam., leafy stems 
2-5 mm thick, glabrous or with short (0.2-0.4 mm) thin 
hairs; stipules 4-6 mm long, 2-4 mm wide at the base. 
Leaves often crowded distally, petioles 7-40 mm, 1-2.5 
mm thick, glabrous or puberulent with short hairs, with- 
out glands; leaf blades 6-22 cm long, 2.5-10 cm wide, 
obovate to elliptic-obovate or oblong-obovate, apex 
bluntly obtuse to rounded, margin entire or slightly cre- 
nate distally with minute glands in shallow (0.2 mm) 
sinuses, tapering gradually to the cuneate base and slight- 
ly decurrent on the petiole, often with 2 narrow glandular 
areas along edge near base, drying dark brown and stiffly 
chartaceous or subcoriacious, glabrous or very sparsely 



puberulent in early stages, 2 veins 5-8/side. Male in- 
florescences 1-4 at older or leafless nodes, 3-8 cm long, 
0.5-1 mm thick, glabrous or with short irregular hairs 
0.2 mm long, glomerules sessile, ca. 2 mm wide, sub- 
tended by minute irregular bracts ca. 1 mm long; $ flow- 
ers with 3-5 calyx lobes, puberulent, filaments 1 .3-2 mm 
long, 0. 1 mm thick, glabrous; anthers 0.2-0.4 mm long, 
0.2-0.3 mm wide. Female inflorescences from older leaf- 
less nodes (axillary), solitary, 2.5-12 cm long, rachis 1- 
1.5 mm thick, hirtellous, flowers subtended by 1-3 bracts 
(sometimes resembling a calyx) 1-1.5 mm long, trian- 
gular, acute, glabrous, pedicels 0.5-1 mm long; $ flowers 
with calyx ca. 3 mm wide, 5-parted, to 1.5 mm long, 
ovary 1 .5-3 mm long, ovoid, covered with short yellow- 
ish hairs, 2-locular in Costa Rica (usually 3-locular in 
South America), style column ca. 1 mm long, 0.6 mm 
thick, style branches 0.5-1 mm long and recurved. Fruits 
10-13 mm long (not including the 1-2 mm high style 
column), ca. 6-9 mm diam., ellipsoid or narrowly ob- 
ovoid, glabrous or sparsely puberulent, smooth; seeds 
6-10 mm long, covered with an orange or red aril. 

Plants of evergreen forest formations on both 
the Caribbean and Pacific slopes, 50-900 m ele- 
vation (to 1 200 m in western Panama). Flowering 
in June-July; fruiting in August-October. The spe- 
cies (in a wide sense) ranges from Costa Rica to 
southern Brazil. 

Richeria obovata is recognized by its stiff sub- 
glabrous leaves with minute or linear glands along 
the entire margins, spicate inflorescences with ses- 
sile glomerules, $ flowers with minute anthers, and 
ellipsoid fruits with colorful arillate seeds. In con- 
trast to collections of this species from Amazonia, 
our plants have ovaries and fruits with two locules 
rather than three. This does not appear to be a 
significant distinction and can be found in some 
collections from Colombia (cf. Zarucchi et al. 
7214}. Amazonian material has considerably 
thicker leaves with more rounded apices, but Co- 
lombian material appears to be intermediate with 
ours. Some Costa Rican collections were misiden- 
tified as R. dressleri Webster, but that species has 
larger leaves with more secondary veins and larger 
foliaceous stipules. Collections placed here include 
Hammel et al. 18499; Hartshorn 1034, 1070, & 
1305; Herrera 4452; and Zamora et al. 1443. 



Ricinus Linnaeus 

Weak-stemmed shrubs or small trees, annual or per- 
sisting for several years, glabrous, often with extra-floral 
nectaries at the nodes; stipules united and solitary at the 
node, large and enclosing the shoot apex, entire, with 
parallel venation, deciduous. Leaves alternate, simple, 
long-petiolate and peltate, glabrous; leaf blades pal- 
mately lobed with serrate gland-tipped margins, vena- 
tion palmate. Inflorescences terminal or axillary to distal 



BURGER & HUFT: FLORA COSTARICENSIS 



149 



leaves, solitary, with a single thick rachis, bisexual (rarely 
9), <J flowers solitary or in alternate small fascicles along 
the rachis proximally, 9 flowers distal on the rachis, short- 
pedicellate, subtended by stipule-like bracts, glabrous, 
pedicels articulated in the middle (<5) or near the apex 
(9). Male flowers globose in bud, sepals 3-5, valvate, 
deciduous or reflexed, petals and disk absent; stamens 
more than 50, filaments united but separate and branched 
distally, each bearing 2-12 anthers, thecae attached sep- 
arately on the connective and divergent, biloculate; pis- 
tillode absent. Female flowers with calyx spathaceous or 
3-5-parted (valvate), deciduous, petals, disk and stam- 
inodes absent; ovary usually covered with conspicuous 
ascending spine-like hairs, 3 locular, ovules 1/locule, style 
short with 3 deeply bifid stigmas, the 6 elongate stigmatic 
branches erose-plumose. Fruits capsules, separating into 
3 2-valved cocci, with longitudinal loculicidal dehis- 
cence, surface echinate to smooth; seeds large with a 
rounded caruncle, surface smooth, lustrous, usually with 
complex patterned coloration. 

The genus consists of a single species, now found 
throughout the tropics and widely cultivated. The 
colorful inflorescences (and leaves in some orna- 
mental cultivars) with 9 flowers distal to the <3, and 
the branched stamens with many anthers make 
the species and genus easily recognizable. The large 
peltate deeply lobed leaves with serrate margins 
are unique among Euphorbiaceae found in Central 
America. 

Ricinus communis L., Sp. PI. 1007. 1753. Figure 1. 

Weak-stemmed shrubs or small trees l-4(-8) m tall, 
leafy stems 3-16 mm thick, hollow or with soft pith, 
glabrous; stipules 9-22 mm long, 4-6 mm broad at the 
base, ovate-lanceolate, pale brown, leaving a scar around 
the stem (except beneath the petiole base). Leaves pel- 
tate, petioles 7-35 cm long, 2.5-12 mm thick, glabrous, 
terete, often with glands at the apex and near the base; 
leaf blades 12-48 cm long, equally wide, with (5-) 7-1 1 
lobes, the distal lobes larger and narrowly ovate-elliptic, 
marginal teeth 0.5-3 mm broad, drying chartaceous, with 
(5-) 7-1 1 palmate 1 veins, the central vein with 10-24 
2 veins/side. Inflorescences 640 cm long, 2-8 cm wide, 
racemose, peduncle 2-20 mm long (much longer in fruit), 
<5 flowers sessile or on pedicels to 1 5 mm long, 9 flowers 
usually congested distally, subtended by linear to ovate 
bracts 1-3 mm long, short-pedicellate. Male flowers 4- 
6 mm diam. in bud, calyx lobes 5-8 mm long, ovate; 
stamens 4-8 mm long, anthers 0.3-0.5 mm long, pale 
yellowish. Female flowers with sepals ca. 5 x 2 mm, 
ovary ca. 3 mm diam., covered with slender-tipped hairs 
becoming 1-6 mm long, pale bluish green to bright red, 
style branches 3-5 mm long, orange to red. Fruits 1 .4- 
2.5 cm long, 1-2 cm diam., oblong with persisting stiff 
spines or smooth, borne on pedicels 2-7 cm long; seeds 
7-16 mm long, 5-10 mm wide, oblong-obovoid, often 
with mottled brown and white patterns on the smooth 
surface, caruncle 2-3 mm wide. 

Occasional plants of weedy secondary vegeta- 
tion and planted in parks and gardens, from near 



sea level to 1 800 m elevation. The species is prob- 
ably native to northeastern Africa; it is now grown 
or naturalized throughout the tropics. 

Ricinus communis is recognized by the larger 
peltate palmately lobed leaves with glandular-ser- 
rate margins. The unique inflorescences, colorful 
unisexual flowers, and distinctive fruits with mot- 
tled seeds further distinguish this species. Extra- 
floral nectaries (glands) are usually present on stems 
and leaves. This species has been cultivated in the 
eastern Mediterranean for more than 5,000 years. 
The seeds contain oils (35-55% by weight) which 
have been used for illumination, lubrication, paints, 
varnishes, plasticizers, soaps, and printing cotton 
goods (Cobley & Steele, 1 976). The oil is also used 
medicinally as a purgative. The seeds also contain 
the poisonous alkaloid ricin, with two to six seeds 
sufficient to kill a person (Mabberley, 1987). 
Standley and Steyermark ( 1 949) report that a larg- 
er black- seeded variety is used in Guatemala for 
machinery oil, while a light and dark brown-seed- 
ed variety is used for medicinal purposes. The 
expressed seed remains are used as a fertilizer; 
stems have been used for making paper. Indicative 
of the range of variation found within this species 
are ornamental varieties with leaves ranging from 
glaucous-blue to dark metallic-red or bright green 
with white venation. Higuerilla and "castor oil 
plant" are common names; the Brunka name is 
sii-krd (Pittier, 1957). The oil is called aceito de 
ricino, aceito de castor, and aceite de palma- Crist i. 



Sagotia Ha i lion 

Shrubs or trees, monoecious or dioecious, latex clear 
or yellowish; stipules enclosing the shoot apex, caducous. 
Leaves alternate, petiolate, margins entire, venation pin- 
nate, mostly glabrous. Male inflorescences terminal or 
axillary, racemose (or branched near base and panicu- 
late), bracts caducous, flowers borne on long distant ped- 
icels; $ flowers with 5 sepals, united near base, lobes 
rounded, imbricate in bud, petals 5, longer than the se- 
pals, apex rounded, imbricate in bud, disk absent; sta- 
mens more than 20, free, closely clustered on the recep- 
tacle on very short filaments, anthers elongate with par- 
allel thecae, dehiscing longitudinally; pistillode absent. 
Female inflorescences terminal or axillary, racemose with 
distant flowers on long pedicels, bracts caducous; 9 flow- 
ers with 5-6 sepals, free to the base, recurved, petals 
absent, disk absent; ovary with 3 locules, styles 3, united 
near the base and bifid distally, ovules 1/locule. Fruits 
capsules, rounded and 3-lobed, subtended by the per- 
sisting calyx, breaking into 3 2-valved cocci; seeds ovoid 
to subglobose, endosperm carnose, cotyledons flat. 

A tropical South American genus of two species, 



150 



FIELDIANA: BOTANY 



one recently discovered in southern Costa Rica 
and adjacent Panama. 

Sagotia racemosa Baillon, Adansonia 1: 54. 1860. 
Figure 20. 

Trees 5-18 m tall, dioecious (rarely monoecious with 
bisexual inflorescences), with clear sap becoming white 
or yellowish with oxidation, leafy stems 1 .5-7 mm thick, 
glabrous (rarely minutely puberulent at first); stipules 4- 
8 mm long, 1.5-2 mm wide at base, acute. Leaves with 
petioles 1.3-5(-7.2) cm long, 1-2.3 mm thick, glabrous, 
sulcate adaxially, thickened and often geniculate at the 
apex; leaf blades 10-24(-28) cm long, 4-12(-14.5) cm 
wide, elliptic-oblong to oblong or ovate-oblong, apex 
bluntly acute to short-acuminate, margin entire, base 
obtuse to acute, drying stiffly chartaceous and brownish, 
glabrous above and below, 2 veins 9-19/side. Male in- 
florescences 3-12 cm long, racemose or paniculate, with 
10-many flowers on long (6-18 mm) slender articulated 
pedicels; $ flowers with calyx lobes 1-2 mm long, ca. 1.5 
mm wide at base, rounded distally and ciliolate, surfaces 
glabrous, petals 3-5 mm long, obovate, broadly rounded 
distally, white at first and turning red, drying black; an- 
droecium 4-8 mm diam., anthers ca. 1.2 mm long, sub- 
sessile. Female inflorescences solitary, 4-8 cm long, rac- 
emose, rachis 1-2.5 mm thick, glabrous or rarely mi- 
nutely puberulent (pubescent in South America), drying 
dark, with 6-1 5 flowers, bracts 3-4 mm long, lanceolate, 
pedicels 1645 mm long; 9 flowers with usually 6 sepals 
4-10(-14) mm long, 1.54(-6.5) mm wide, narrowly ob- 
long to obovate or ovate, apex rounded, green and stiff, 
with parallel venation; ovary 2-3 mm long, 2.5-3.5 mm 
diam., covered with short dense yellowish white hairs, 
styles united for ca. 1 mm, branches to 4 mm long, 0.4 
mm thick. Fruits 14-20 mm long, 16-26 mm wide, 
3-lobed and rounded, bright green; seed 16x15x14 
mm (based on McPherson 12476), subglobose. 

Trees of evergreen lowland rain forest forma- 
tions, 10-1200 m elevation (in South America). 
Flowering in May, August, and November-De- 
cember; fruiting in March-April. In southern Cen- 
tral America, this species has been collected only 
at 200-300 m elevation, on the Osa Peninsula 
(Hammelet al. 16784 & 16799, Marin 100, 301) 
and in Bocas del Toro (McPherson 1 1823 & 12470). 
The species ranges disjunctly from southern Costa 
Rica and adjacent Panama to the Amazon basin. 

Sagotia racemosa is recognized by its restricted 
habitat (in Central America), general lack of pu- 
bescence, petioles thickened near the apex, $ flow- 
ers with sepals, petals, and dome-like androecium, 
larger 9 flowers that dry black, and large seeds. 



Sapium P. Browne 

REFERENCES M. J. Huft, Four new species of 
Sapium (Euphorbiacae) from Central and South 



America. Phytologia 63: 443^48. 1987. E. Ja- 
blonski, Notes on Neotropical Euphorbicaceae, 3. 
Synopsis of Caribbean Sapium. Phytologia 16: 
393-434. 1 968. R. C. Kruijt, Monographic studies 
on Sapium (Euphorbiaceae, Hippomaneae) and 
related genera. Thesis, Institut voor Systematische 
Plantkunde der Rijksuniversitat Utrecht. 1 989. H. 
Pittier, The Mexican and Central American spe- 
cies of Sapium. Contr. U.S. Natl. Herb. 12: 159- 
169. 1908. 

Trees or shrubs monoecious (dioecious), stems with 
milky latex, nearly always glabrous; stipules small, often 
becoming thickened and persistent. Leaves alternate, 
simple, petiolate, usually with 2 prominent adaxial glands 
at the apex of the petiole or base of blade, glabrous, entire 
or glandular-serrate, apex sometimes cuculate-reflexed, 
glabrous, pinnately veined. Inflorescences terminal (rarely 
axillary), solitary (rarely 2-5), bisexual or unisexual, ra- 
chis unbranched, usually thick and glabrous, bracts usu- 
ally with 2 (3) large flat appressed lateral glands, 2 flowers 
proximal and 1 /bract, $ flowers in distal sessile glom- 
erules of 2-16. Male flowers sessile or pedicellate, gla- 
brous, calyx united at the base, 2-lobed, open or sub- 
imbricate, corolla and disk absent; stamens usually 2, 
exserted. Filaments free or united at base, anthers 
2-thecous, dehiscing longitudinally, extrorse; pistillode 
absent. Female flowers glabrous, calyx united near the 
base (rarely more), 2- or 3-lobed or parted or irregular, 
corolla and disk absent; ovary sessile or stipitate, locules 
1-3, ovules 1/locule, styles (1) 2-3, usually united at 
base, simple, distally recurved. Fruits capsules (some- 
times indehiscent), with 3 (2) 2-valved cocci, woody or 
somewhat fleshy, columella usually persisting; seeds 
rounded in outline, lenticular to wedge-shaped, often 
rugulose, with a thin fleshy red or white aril, ecaruncu- 
late. 

A genus recently interpreted as having 2 1 Neo- 
tropical species (Kruijt, reference above) but also 
interpreted as being pantropical with 90-100 
mostly Neotropical species (Webster, 1 994b). Re- 
gardless of circumscripton, Sapium has been con- 
sidered one of the most difficult genera of Eu- 
phorbiaceae as regards the identification and sep- 
aration of species. This appears to be due in part 
to great morphological variation among different 
individuals of what are probably the same species. 
In addition, flowering and fruiting inflorescences 
differ greatly on the same tree, and vegetative mor- 
phology can vary greatly within a single popula- 
tion. Rather than create more confusion, we have 
decided to follow Kruijt's approach (reference 
above) with only a few exceptions. Thus, the vast 
majority of Costa Rican collections are now placed 
under 5. glandulosum(q.v.). Unfortunately, Kruijt 
did not see material at F or us, some of his de- 
scriptive terminology is unconventional, and his 
thesis work has not been published. We thank the 



BURGER & HUFT: FLORA COSTARICENSIS 



151 



library of the Missouri Botanical Garden for loan 
of Kruijt's thesis. 

Specimens of Sapium are usually easy to rec- 
ognize because of their glabrous parts, white latex, 
petioles with prominent glands near the apex, stiff 
leaves, thick spicate inflorescences, floral bracts 
with paired rounded flat appressed glands, prox- 
imal 9 flowers (1 /bract) and distal sessile glom- 
erules of $ flowers with two stamens, and seeds 
with an aril. The flowering spikes can be quite long 



but the <3 portion breaks off and fruiting spikes are 
usually less than 1 cm long. A number of South 
American species have latex that has been used as 
a source of rubber. Triadica sebifera (L.) Small 
(formerly Sapium sebiferwn (L.) Roxb., the "Chi- 
nese tallow tree") from China and Japan is planted 
as an ornamental in subtropical areas. Members 
of the genus are frequently called yos in Costa Rica. 
Compare Stillingia. 



Key to the Species of Sapium 

la. Inflorescences axillary, infructescences borne laterally at leafless nodes [leafy stems to 12 mm thick 
with rough persisting stipules, leaf blades with 15-28 2 veins/side; 10-1200 m elevation on the 
evergreen Pacific slope of southern Costa Rica] S. allenii 

Ib. Inflorescences terminal, infructescences never below leafless nodes of the same axis (but new lateral 
shoots are often present and may arise from the base of the inflorescence or infructescence ... 2 

2a. Inflorescences and infructescences 2-5 at the apex of the stems [bracts deciduous beneath the older 
2 flowers, fruits ca. 8-10 mm diam.; venation arising at 70-90 from the midvein, with 1 5-30 veins/ 
side] S. laurifolium 

2b. Inflorescences and infructescences solitary at the apex of stems 3 

3a. Secondary veins dichotomizing 2-5 mm from the leaf margin, Y-shaped distally and arising from 
the midvein at angles of 80-90 [blades 3-1 1 cm long; fruits on short (24 mm) stipes; montane 
forest trees at 1 200-2200 m elevation] S. rigidifolium 

3b. Secondary veins not dichotomizing distally, arching upward near the margin with only minor distal 
lateral branches 4 

4a. 2 flowers subtended by 3 thin erect rounded bracts in addition to the biglandular bract; seeds 6.5- 
9 mm long; distal flowering stems thick (3-9 mm) and knobby with raised leaf scars and thickened 

stipules [inflorescences axes 2-8 mm thick, fruits sessile; montane forests 1 100-2200 m] 

S. pachystachys 

4b. 2 flowers subtended by only 1 sessile biglandular bract; seeds 3.8-7.6 mm long; distal flowering 
stems usually not so thick and knobby 5 

5a. Fruits stipitate on stipes 3-8 mm long, often pyriform or ellipsoid, distant along the rachis, 10-14 
mm diam., seeds 7-7.6 mm long; perianth not reddish; leaf blades often oblong and acute at both 
apex and base S. macrocarpum 

5b. Fruits sessile or short-stipitate (stipes to 3 mm long), oblate to globose, never pyriform or ellipsoid, 
to 12 mm diam., usually closely crowded on the infructescence, seeds 3.8-6.7 mm long; perianth 
sometimes reddish; leaf blades variable, entire to serrulate, acute to rounded at apex or base [wide- 
spread species, frequently collected] S. glandulosum 



Sapium allenii Huft, Phytologia 63: 443. 1987. 
Figure 22. 



Trees 1 2-25 m tall, monoecious, leafy stems 5-12 mm 
thick, glabrous, becoming rough and knobby with thick- 
ened persisting stipules; stipules 5-7 mm long, 3-4 mm 
wide at base, triangular, glabrous, becoming thickened. 
Leaves clustered near the apex, petioles 3-5.5 cm long, 
1.3-2 mm thick, glabrous, glands opposite or subop- 
posite and adaxial near the apex, 0.5-2 mm long, cylin- 
dric; leaf blades 11-21 cm long, 4-9 cm wide, oblong to 
elliptic-oblong, apex short-acuminate or obtuse, flat or 



often folded, margin entire or slightly undulate with min- 
ute (0.2 mm) glandular areas along the edge, often rev- 
olute, base obtuse, drying stiffly chartaceous, glabrous, 
2 veins 1 5-28/side (intersecondaries often prominent). 
Inflorescences lateral, borne at 45-90 angle from leafless 
nodes, 2.5-6 cm long in fruit (not seen at anthesis), rachis 
3-5 mm thick, glabrous, bracts ca. 2 mm long, 3 mm 
broad at the base, smooth and rounded, 6 flowers not 
seen, 9 flowers with stipes becoming 4-5 mm long and 
1-1.5 mm thick in fruit. Fruits 7-9 mm long, 5-1 1 mm 
wide, smooth and green, glabrous, columella, ca. 6 x 
1 .4 mm, 2-3 mm wide at the apex, slightly winged; seeds 
4.5-6 mm long, 4-5.2 mm wide, 3-3.5 mm thick, some- 



152 



FIELDIANA: BOTANY 



what lenticular with circular outline, tuberculate, with 
thin ridged margin around the periphery, reddish. 

Plants of evergreen rain forest formations of the 
Pacific slope, 10-1200 m elevation. Fruiting in 
January-March. Now known from three collec- 
tions: Allen 5773 (the type) from near Palmar Sur 
de Osa, Gomez- Laurito 11916 from the Jardin 
Botanico Wilson, and Skutch 4821 from the Gen- 
eral Valley. The species is known only from south- 
ern Costa Rica. 

Sapium allenii is recognized by its short lateral 
inflorescences from leafless nodes, stipitate fruits, 
and usually oblong leaves with many secondary 
veins. Note that the perianth or perianth scars are 
at the base of the fruit stalk; it is a stipe, not a 
pedicel. The thick stems with persistent stipules 
resemble those of S. pachystachys (q.v.). Sapium 
lateriflorum Hemsl. of Mexico and northern Cen- 
tral America is the only other species in this region 
with lateral inflorescences, but it has more slender 
stems with the smaller stipules usually deciduous, 
2 veins that are more strongly ascending, usually 
more numerous spikes on a branchlet, and some- 
what larger fruits. Kruijt did not see material of 
S. allenii. 

Sapium glandulosum (L.) Morong, Ann. New York 
Acad. Sci. 7: 227. 1893. Hippomane glandulosa 
L., Sp. PI. 1191. 1753. S. aucuparium Jacq. 
Enum. pi. syst. 31. 1760. S. pittieri Huber, Bull. 
Herb. Boissier, Ser. 2, 6: 350. 1906. S. oligo- 
neurum K. Schum. & Pittier, Contr. U.S. Natl. 
Herb. 12: 168. 1908. S. sulciferum Pittier, Contr. 
U.S. Natl. Herb. 12: 169. 1908. S. biglandulos- 
um (L.) Mull. Arg. var. oligoneurum Monach., 
Bull. Torrey Bot. Club 67: 772. 1940. S. big- 
landulosum (L.) Mull. Arg. var. sulciferum (Pit- 
tier) Monach., Bull. Torrey Bot. Club 67: 772. 
1940. S. schippii Croizat, Amer. Midi. Nat. 29: 
477. 1943. Figures 22 and 23. 



Trees (3-)5-20 m tall, sap white and thick, leafy stems 
1.8-7 mm thick, glabrous; stipules 2-3 mm long, 1-2 
mm wide, triangular-ovate, appressed, often rounded at 
base. Leaves often clustered distally, petioles 6-30 mm 
long, 0.7-1.3 mm thick, glabrous, sulcate above, paired 
lateral glands opposite or subopposite at apex, to 1 mm 
high, 0.5-0.9 mm diam., cylindrical, rarely borne on the 
lamina base; leaf blades 3-14(-18) cm long, 1.8-5(-8) 
cm wide, elliptic-oblong to oblong (broadly elliptic or 
broadly oblong in smaller leaves), apex acuminate or less 
often rounded, the tip rounded, folded or cucullate, mar- 
gin entire or subentire with minute glands along the edge, 
often revolute on drying, base obtuse to acute, drying 
stiffly chartaceous or subcoriaceous, glabrous, 2 veins 
6-14(-20)/side. Inflorescences terminal, solitary (2-3), 



spiciform, 3-15 cm long, rachis 1.5-2 mm thick, gla- 
brous, both <? and 2 bracts small and inconspicuous but 
with large (1.5-2.3 mm diam.) circular or oblong flat 
appressed bracts, bracts and perianth greenish, 9 flowers 
solitary, S flowers 3-9/bract, pedicels < 0.5 mm long, 
thick. Male flowers with calyx 1.2-2 mm long, united 
to form a conic tube, 0.7-1.5 mm long, 2-lobed, trans- 
lucent; stamens with filaments 1-1.4 mm long, anthers 
0.4-0.8 mm wide. Female flowers subsessile, sepals 0.7- 
1 mm long, thin, often obscured by bracts and glands; 
ovary 2-2.5 mm long, 1.8-2.8 mm diam., styles 3, col- 
umn 0.5-1.5 mm long, style branches 3, 1.5-2.5 mm 
long and recurved. Fruits 6-10 mm long, 8-1 3 mm wide, 
oblate, smooth, green with purple distally, sessile or on 
short (2.5 mm) stipes, columella 4-6 mm long, ca. 0.7 
mm thick; seeds 4.5-6.5 mm long, 3.8-6 mm wide, 2.8- 
4 mm thick, rounded in outline and often thick-lentic- 
ular, surface muricate or warty, red (drying whitish). 

Common trees found in evergreen and decid- 
uous forests, 2-2200 m elevation. In Costa Rica, 
the species is collected most often between 900 
and 2000 m. Flowering in February-June; fruiting 
primarily in June-October. The species (in a wide 
sense) ranges from Mexico to Paraguay and the 
West Indies (except Cuba and Haiti). 

Sapium glandulosum is recognized by its entire 
(rarely serrulate) leaves, solitary inflorescences, 
three-style branches, and smaller subsessile or 
short-stipitate fruits often crowded on the infruc- 
tescence. The leaf tips may be distinctively cu- 
cullate or folded at higher elevations. Also, the 
leaves are generally smaller but with relatively 
broader blades and with abruptly rounded leaf api- 
ces at higher elevations, helping distinguish this 
species from the very similar S. macrocarpum, but 
fruiting material is necessary to be certain. In the 
type of S. pittieri (Pittier 4344 us), the glands are 
along the base of the leaf blade and not at the apex 
of the petiole. But this character is seen in a few 
other highland collections and does not appear to 
be significant. A few collections from the Osa Pen- 
insula have leaves with abruptly rounded apices. 
Plants of the La Selva area are distinctive in often 
lacking the many 2 veins arising at right angles 
from the midvein, and the $ calyx is often com- 
pletely connate to form an urceolate reddish tube. 
The senior author's attempts to separate these 
many variants into meaningful "species" were not 
successful, and he has chosen to follow Kruijt in 
placing all this diverse material under the Lin- 
naean name. However, our description is based 
only on Costa Rican material. This is our most 
commonly collected species of Sapium and, like 
the others, often called yos. 

Sapium laurifolium (A. Rich.) Griseb., Fl. Brit. W. 
Ind. 49. 1859. Stillingia laurifolia A. Rich., His. 



BURGER & HUFT: FLORA COSTARICENSIS 



153 



Fl. Cuba 1 1 : 20 1 . 1 850. Sa. jamaicense Sw. (nom. 
illeg., fide Kruijt), Adnot. Bot. 62. 1829. Sa. 
anadenum Pitt., Contr. U.S. Natl. Herb. 12: 164. 
1 908. Sa. pleiostachys K. Schum. & Pitt., Contr. 
U.S. Natl. Herb. 12: 164. 1908. 

Trees 8-25 m tall, monoecious, leafy stems 2-10 mm 
thick, glabrous; stipules 1-3 mm long, triangular, be- 
coming thickened and rounded with thin lateral margins, 
persisting. Leaves with petioles 15-35(-52) mm long, 1- 
1.5 mm thick, usually with 2 small (0.7 mm) lateral 
glands near the apex; leaf blades 6-15(-20) long, 3-6(- 
9) cm wide, elliptic-oblong to narrowly oblong, apex 
usually short-acuminate, margin entire or with a few 
marginal glands, base acute to obtuse, drying stiffly char- 
taceous, glabrous above and below, 2 veins 20-30/side, 
arising at angles of 70-85. Inflorescences apical, usually 
2-5, unisexual or bisexual, 2-1 2(-28) cm long, peduncles 
very short, bracts subtending 9 flowers often quickly ca- 
ducous and leaving a round scar, $ bracts subtending 3- 
6 flowers, glands 1-2 mm long and flat, rounded to ob- 
long. Male flowers sessile or subsessile, calyx ca. 1 .4 mm 
long, with 2 lobes ca. 4 mm long, yellowish to red; fil- 
aments free, ca. 1.8 mm long. Female flowers with calyx 
ca. 1.5 mm long, trilobed, ovary ca. 1-2 mm long, sub- 
globose, style branches 3, deciduous and leaving a round- 
ed whitish scar. Fruits 7-8 mm long, 7.5-10 mm wide, 
oblate to broadly ovate with 3 longitudinal sulci; seeds 
4-6 mm long, 3-5 mm wide. 

Plants of evergreen rain forest formations, 0- 
1 200 m elevation on the Caribbean slope and in 
the Golfo Dulce area. Flowering in March; fruiting 
in September. The species ranges from Costa Rica 
to Brazil and the greater Antilles. 

Sapium laurifolium is recognized by the usually 
clustered terminal spicate inflorescences, bracts 
deciduous beneath the 9 flowers, and small fruits 
with thin capsule wall. A short flowering season 
may explain why there are so few collections of 
this species from Costa Rica. Vegetatively, this 
species is very similar to S. glandulosum, and the 
two may be indistinguishable in the absence of 
inflorescences. It is possible that they are conspe- 
cific. 

Sapium macrocarpum Mull. Arg., Linnaea 32: 1 1 9. 
1863. S. mexicanum Hemsl. in Hooker, Icon. 
PI. 2680. 1901. S. thelocarpum Schum. & Pit- 
tier, Contr. U.S. Natl. Herb. 12: 166, pi. 13. 
1908. Figure 23. 

Trees 8-35 m tall, leafy stems 1.4-5 mm thick, gla- 
brous, (rarely minutely puberulent); stipules 1-2.8 mm 
long, ovate-triangular, acute, often with thin undulate 
margins, persistent. Leaves distant or closely clustered 
distally, petioles 7-40 mm long, 0.7-1.4 mm thick, gla- 
brous, distal paired glands 0.7-1 mm long, 0.4-0.7 mm 
diam., cylindrical to conical; leaf blades 4-15 cm long, 



1.7-4.5 cm wide, narrowly elliptic-oblong to narrowly 
oblong or lanceolate, usually tapering gradually to an 
acute apex, tip rounded and often adaxially recurved, 
margin subentire or obscurely serrulate with teeth 0.1- 
0.3 mm high, base acute to obtuse and rounded, drying 
stiffly chartaceous and often yellowish beneath, glabrous, 
2 veins 6-13/side. Inflorescences terminal, solitary, bi- 
sexual, (3-)7-15(-22) cm long, rachis 2-3.5 mm thick, 
glabrous, 9 flowers 3-10 at proximal nodes, $ flowers 7- 
1 l(-16)/bract, bracts 1.5-3 mm long, flat, appressed, 
round or oblong. Male flower buds ca. 2 x 1.5 mm, 
obovoid, subsessile at anthesis, calyx 2-2.5 mm long, 
lobes ca. 0.5 mm long, anthers ca. 0.6 mm long, ca. 0.9 
mm wide. Female flowers sessile, calyx parts 1-3 mm 
long, ovary 2-5 mm long, 1.5-4 mm diam., ellipsoid, 
narrowed at the base and often becoming stipitate, style 
column 0.5-1 mm long, free styles ca. 2 mm long and 
recurved. Fruits to 2 cm long, 1-3 cm diam., stipitate 
and usually pyriform or obovoid, distant on the rachis; 
seeds 7.2-7.6 mm long, 5.8-7 mm wide, 5.2-5.5 mm 
thick, whitish or reddish. 

Plants of both evergreen and partly deciduous 
forest formations (rarely collected in deciduous 
forest in Costa Rica), (100-)700-1800 m eleva- 
tion. Flowering in April-July; fruiting in May- 
November. The species ranges from Mexico to 
central Costa Rica. 

Sapium macrocarpum is characterized by the 
distant stipitate pyriform to ovoid and smooth 
fruits. Additional characteristics are the usually 
narrowly oblong leaves tapering to both apex and 
base and the often recurved leaf tips. This species 
can become a huge tree (Bella 1499). Herbarium 
specimens of this species may be impossible to 
separate from those of S. glandulosum (sensu laid) 
in the absence of mature fruit. We follow Kruijt's 
nomenclature for this species. 

Sapium pachystachys Schum. & Pittier, Contr. U.S. 
Natl. Herb. 12: 168, t. 16. 1908. Figure 22. 

Trees 8-25 m tall, monoecious, leafy stems 2.7-9 mm 
thick, glabrous, older stems with thick stipules and raised 
leaf scars; stipules 4-8 mm long, triangular, appressed, 
persistent, becoming thickened. Leaves usually closely 
clustered distally, petioles 1.7-6(-l 1) cm long, 1-2. 7 mm 
thick, glabrous, glands opposite or subopposite near apex, 
to 1.5 m long, 0.5-0.9 mm thick, cylindrical or conical; 
leaf blades (8-)10-20(-26) cm long, (2.0-)3-7(-8.5) cm 
wide, elliptic, elliptic-oblong, to oblong, apex bluntly 
acute to obtuse (subacuminate), tip flat or cucullate, mar- 
gin entire or slightly crenate with lobes 0.3 mm high, 
base obtuse to rounded, drying chartaceous to stiffly 
charcateous, often yellowish or grayish, glabrous, 2 veins 
8-20/side. Inflorescences terminal, solitary, bisexual or 
<5, 8-25 cm long, rachis 2-5 mm thick (to 8 mm thick 
in fruit), glabrous, 9 bracts ca. 3 x 6 mm, broadly sessile, 
with 2 lateral flat rounded or oblong glands 2.5-4 mm 
diam., S bracts subtending 5-1 1 flowers, glands sessile 
and appressed, <5 pedicels ca. 1 mm long. Male flowers 



154 



FIELDIANA: BOTANY 



with calyx 1.2-2 mm long, united and 2-lobed; stamens 
free, filaments 0.7-2 mm long, anthers 0.7-1 mm long, 
1-1.5 mm wide. Female flowers subtended by 3 thin 
rounded bracts (in addition to the sessile biglandular 
bract), perianth 2-5 mm long, to 3 mm wide, 3-lobed, 
resembling the subtending bracts in texture; ovary glo- 
bose, style column 1.5-4 mm long, to 1.3 mm thick, 
style branches 2-3 mm long, recurved and coiled. Fruits 
8-16 mm long, 10-16 mm diam., subsessile, columella 
ca. 8 mm long, 2.5 mm thick and 3-4 mm wide at the 
apex; seeds 6.5-9 mm long, 6.5-8 mm wide, 4-5 mm 
thick, ovate to orbicular in outline, lenticular with a 
narrow circumferential margin, rugulose or verrucose, 
aril white to red. 

Plants of lower montane evergreen forest for- 
mations, 1 100-2200 m elevation (700-2100 m in 
Panama). Flowering in October and December- 
May; fruiting in June-October. The species ranges 
from Costa Rica's central volcanic chain (Volcan 
Poas) to western Panama. 

Sapium pachystachys is recognized by its high- 
land habitats, thick stems with prominent leaf scars 
and thickened persisting stipules, three thin 
rounded bracts between the glandular bract and 
the 9 calyx, and subsessile fruits. Leafy stems can 
be very similar to S. allenii, which is a lower el- 
evation species. Specimens of this species with 
immature inflorescences may be very difficult to 
separate from S. glandulosum. Our interpretation 
of this species agrees with that of Kruijt. 

Sapium rigidifolium Huft, Phytologia 63: 444. 
1987. Figure 23. 

Trees 8-30 m tall, trunk to 80 cm diam., monoecious, 
leafy stems (1.5)-2-6 mm thick, glabrous, dark brown, 
becoming bumpy with thickened stipules and raised leaf 
scars; stipules 2-3.5 mm long, 1.3-1.8 mm wide, ovate, 
usually with thin margins and thick center. Leaves clus- 
tered near the ends of branchlets, petioles 8-28 mm long, 
1-1.7 mm thick, glabrous, drying dark, sulcate above, 
with 2 apical adaxial glands, opposite or subopposite, to 
1 mm long, 0.6-1 mm diam.; leaf blades (3-)4-l 1 cm 
long, (1. 4-) 1.8-4.5 cm wide, oblong to elliptic-oblong 
(lanceolate, elliptic-obovate), apex rounded or emargin- 
ate, glandular and often recurved, margin subentire or 
slightly crenulate (4-6 teeth/cm), base acute or obtuse, 
thickened and decurrent at the glands, drying stiffly char- 
taceous, glabrous, lustrous above, 2 veins 16-40/side, 
arising at 80-90, dichotomizing 2-5 mm from the edge 
and irregularly loop-connected, 3 veins prominent. In- 
florescences terminal, solitary, bisexual, 5-9 cm long, 
spicate, rachis ca. 1.5 mm thick, glabrous, drying dark, 
bracts ca. 0.7 mm long, with 2 lateral thin flat appressed 
rounded glands 1 .4-2 mm diam., <3 bracts subtending 3- 
8 flowers. Male flowers with cupular calyx 1.5-2 mm 
long, 2-lobed; stamens with filaments ca. 1.2 mm long, 
anthers ca. 0.5 x 0.9 mm. Female flowers with thin 
bract-like perianth, 0.7-1 .5 mm long; stipe 2-3 mm long, 
to 1 mm thick, ovary 2-3 mm long, 1-1.4 mm diam., 



ellipsoid, styles 3, column 0.8-1.3 mm long. Fruits ca. 
6x8 mm, broadly ovoid to subglobose, drying dark, 
smooth and glabrous, borne on a stipe 2-4 mm long; 
seeds 4.3-5 mm long, 3.5-4 mm wide, 2-2.2 mm thick, 
oblong in outline, surface tuberculate or with short lon- 
gitudinal ridges. 

Plants of lower montane evergreen cloud forest 
formations, (1200-)! 500-2200 m elevation. 
Flowering in June-July; fruiting in August. The 
species ranges from the Cordillera de Tilaran to 
the Chiriqui Highlands of Panama. 

Sapium rigidifolium is recognized by its lower 
montane habitat, lack of pubescence, stiff smaller 
leaves with unusual secondary veins, stipitate ova- 
ry, and apparently articulated style column. Note 
that the fruit is borne on a stipe with perianth or 
perianth scars at the base (not a pedicel). This 
species, like its congeners, is called yos in Costa 
Rica. Kruijt (cited above) included this species 
within S. stylare Mull. Arg., and it may prove to 
be a subspecific element of that species. We main- 
tain it here on the basis of its smaller fruits, more 
uniform foliage morphology, and distant allopa- 
try. 



Sebastiania Sprengel 

Shrubs or trees (rarely annual herbs), monoecious or 
dioecious; stipules minute, usually caducous. Leaves al- 
ternate (rarely opposite), short-petiolate, blades serrate 
to rarely entire, pinnately veined, with or without glands 
at the base. Inflorescences terminal or leaf-opposed, rare- 
ly axillary or from the internodes, solitary (rarely fascic- 
ulate), unisexual or more often bisexual with 1 (2-5) 
proximal 9 flower and a single unbranched rachis with 
alternate bracts with <5 floweres, bracts with 2 lateral 
glands or glandular areas, $ flowers 1-3/bract, sessile or 
pedicellate. Male flowers small, calyx united at the base, 
2-3-lobed, often open before anthesis, corolla and disk 
absent; stamens 3 (2, 4), filaments free or united at base, 
anthers small, longitudinally dehiscent, extrorse; pistil- 
lode absent. Female flowers with calyx 3-parted or 
3-lobed, corolla and disk absent, staminodes absent; ovary 
with 3 (2) locules, ovules 1/locule, styles 3 (2), free or 
united at the base, simple. Fruits capsules, globose or 
3-lobed, breaking into 3 2-valved cocci, surface smooth 
or armed with projections, usually with 3 (2) seeds, col- 
umella persisting; seeds subglobose to cylindrical, ca- 
runculate. 

A genus of 90-100 species, nearly all Neotrop- 
ical, with a few in Asia, North America, and Aus- 
tralasia. The genus is distinguished by its locules 
with solitary ovules, biglandular bracts, $ flowers 
usually with three stamens and three calyx lobes, 
and fruit often with projections on the lateral sur- 
faces. 



BURGER & HUFT: FLORA COSTARICENSIS 



155 



Key to the Species of Sebastiania 

la. Herbs of open sites in lowland evergreen or partly deciduous areas, to 0.6 m tall; 2 flowers often 
solitary on the internodes S. corniculata 

Ib. Shrubs or trees, usually > 1 m tall; 2 flowers never borne on the internodes 2 

2a. Plants of deciduous areas in northwestern Costa Rica, 0-300 m elevation; 2 veins not loop-connected 
near the margin S. pavoniana 

2b. Plants of montane evergreen forests in western Panama, 900-1500 m elevation; 2 veins loop- 
connected near the margin S. panamensis 



Sebastiania corniculata (Vahl) Mull. Arg. in DC, 
Prodr. 15 (2): 1168. 1855. Tragia corniculata 
Vahl. Ecolog. Amer. 2: 55, pi. 19. 1798. Figure 
11. 

Herbs 1 5-60 cm tall, monoecious, erect or decumbent, 
few- or many-branched, sometimes forming clumps, oc- 
casionally with opposite branching near the base, leafy 
stems 0.4-2 mm thick, with thin straight or curved hairs 
0.4-1.8 mm long; stipules obscure. Leaves alternate (ex- 
cept at base), petioles 1.5-7(-l 1) mm long, 0.2-0.6 mm 
thick, hirsute; leaf blades 11-40 mm long, 3-18 mm 
wide, lanceolate to ovate-lanceolate (linear-lanceolate), 
gradually narrowed to the acute apex, margin minutely 
serrulate or subentire, base obtuse or rounded (rarely 
cordate), drying thinly chartaceous, with thin straight 
hairs above and below (rarely glabrous), venation pin- 
nate, 2 veins 5-8/side. Inflorescences opposite the leaves 
and solitary, bisexual with a single basal 9 flower or <3, 
the S flowers subsessile and alternate along a slender 
spike 4-12 mm long, rachis with short (0.2-0.3 mm) 
thin hairs, solitary 9 flowers also arising from the stems 
between the nodes. Male flowers subtended by serrate 
bracts ca. 0.5 mm long, pedicels 0-0.5 mm long, calyx 
lobes ca. 0.5 mm long; stamens 3, anthers 0.3-0.4 mm 
long. Female flowers with inconspicuous basal calyx lobes 
ca. 0.3 mm long, ovary ovoid or urceolate in form, with 
6 horn-like lobes at the apex and with similar scale-like 
processes on the surface. Fruits 4-5 mm long, ca. 4 mm 
wide, with the distal lobes ca. 1 mm long and additional 
scale-like processes (1 x 1.3 mm) on the sides, usually 
glabrous, columella 2.7-3.4 mm long, 0.8-2 mm wide, 
distally; seeds 2.4-2.6 mm long (not including the ca- 
runcle), 1 .8-2.2 mm wide, ca. 1 .5 mm thick, oblong with 
truncated apex, smooth, caruncle distal and slightly stip- 
itate, 0.5-0.7 mm long, knob-like. 

Weedy plants of open sunny sites in lowland 
evergreen or partly deciduous areas. This species 
has been collected in Costa Rica only near the 
Caribbean shore at Barra del Colorado; flowering 
and fruiting in January-March (Stevens 24165 & 
25040 MO). This species ranges from Cuba and 
Hispaniola to southern Brazil; it is rarely collected 
in southern Central America. 

Sebastiania corniculata is recognized by its small 
weedy habit, narrow hirsutulous leaves, leaf-op- 
posed <3 spikes, and unusual 2 flowers often borne 
on the stem between nodes. The fruits bear several 



triangular acute projections on the surfaces that 
dry dark against the paler yellowish color of the 
capsule wall. The slightly stipitate caruncle is also 
noteworthy. The stem hairs are multicellular, but 
this is difficult to see ( x 50). 



Sebastiania panamensis Webster, Ann. Missouri 
Bot. Gard. 75: 1128. 1988. 

Shrubs or small treelets, (0.5-)l-4(-6) m tall, mon- 
oecious, leafy stems 0.7-3.5 mm thick, with erect or 
appressed hairs 0.1-0.4 mm long, glabrescent; stipules 
0.4-1. 2(-2.5) mm long, 0.8-1.5 mm wide at base, ca- 
ducous. Leaves with petioles 2-8 mm long, 0.4-1.8 mm 
thick, minutely pubescent or glabrous, sulcate adaxially; 
leaf blades 3-16 cm long, 0.6-5 cm wide, lanceolate to 
elliptic-lanceolate, elliptic-oblong, or oblong-lanceolate, 
tapering gradually to an acute or acuminate apex, tip 3- 
1 6 mm long, margins minutely (0.2-0.3 mm) denticulate 
with 1-5 teeeth/cm, base cuneate or slightly rounded, 
drying stiffly chartaceous, glabrous above and below ex- 
cept for small hairs along the midvein, 2 veins 5- 107 
side, loop-connected 1 4(-6) mm from the edge. Inflo- 
rescences leaf-opposed or pseudoterminal, solitary, 1-5 
cm long, usually bisexual with 1 proximal 2 flower, rachis 
with minute hairs, bracts subtending 9 flowers with ob- 
long glands 1.3 mm wide, bracts subtending $ flowers 
with rounded disk-like glands ca. 0.8 mm diam. Male 
flowers on pedicels 0.7-1.5 mm long, calyx 3-lobed; sta- 
mens 34, filaments ca. 0.7 mm long, anthers 0.3-0.4 
mm long. Female flowers subsessile or on short (1.5 mm) 
pedicels, calyx 0.7-1 mm long, covering the ovary in 
bud, ovary ca. 1.3 x 1.2 mm, styles united for 0.6 mm, 
branches ca. 2 mm long. Fruits 6-7 mm long, ca. 7 mm 
wide, with 6 subapical projections to 0.7 mm long, col- 
umella 44.5 mm long, ca. 3 mm wide at apex; seeds 
4.6-5 mm long, 3.5-4 mm wide, 3.2-3.5 mm thick, trun- 
cated at the base and ovoid, caruncle 1.2-1.4 mm wide. 

Plants of evergreen cloud forest formations, 900- 
1 500 m elevation. Probably flowering and fruiting 
throughout the year. This species is found only in 
the highlands of western Panama. 

Sebastiania panamensis is distinguished by its 
montane forest habitat, leaves with loop-connect- 
ed secondary veins, leaf-opposed inflorescences, 
and floral bracts with conspicuous thick flattened 
glands. 



156 



FIELDIANA: BOTANY 



Sebastiania pavoniana Mull. Arg. in DC., Prodr. 
15 (2): 1189. 1866. Figure 25. 

Shrubs or small trees, 3-15 m tall, sap whitish, leafy 
stems 0.8-2 mm thick, glabrous; stipules 0.3-0.8 mm 
long, leaving a scar ca. 0.3 mm wide. Leaves with petioles 
3-1 1 mm long, 0.4-1 .2 mm thick, glabrous, sulcate adax- 
ially, usually with 1-4 minute (0.2 mm) glands at the 
apex adaxially; leaf blades 3-9(-12) cm long, 1.4-3.5(- 
4.8) cm wide, elliptic-oblong to ovate-elliptic, elliptic or 
oblong, apex acuminate with narrow tip 3-10 mm long, 
margin minutely (0.2-0.4 mm) denticulate and some- 
times with dark glandular tips 0.1-0.2 mm long, base 
obtuse or acute, drying chartaceous, greenish, glabrous 
above and below, 2 veins 4-7/side, distally arcuate- 
ascending. Inflorescences terminal or leaf-opposed, bi- 
sexual inflorescences 1 .4-7 cm long, ca. 4 mm wide with 
distal flower groups closely approximate or separate, ra- 
chis 0.4-1 mm thick, glabrous, 9 inflorescences 6-1 1 mm 
long, with 1-3 flowers, rachis ca. 0.8 mm thick, bracts 
broadly sessile, with glandular areas, stinging hairs often 
present near the flowers. Male flowers subtended by bracts 
ca. 1 mm long, 1 .4 mm broad at the base; stamens usually 
3/flower, filaments 0.4 mm long, anthers 0.3-0.4 mm 
long. Female flowers subtended by bracts ca. 1 x 1.4 
mm, perianth parts to 1 .4 mm long and bract-like, broad- 
ly imbricate, ovary ca. 1.3 x 1.1 mm, styles 1-2 mm 
long, recurved. Fruits rarely collected, externally smooth, 
coiled dehisced valves ca. 1 1 mm long, columella 5-7 
mm long; seeds 4 mm long, globose, smooth, dark and 
mottled. 

Plants of seasonally very dry deciduous forest 
formations, 0-300 m elevation. Flowering collec- 
tions have been made in February-June and Sep- 
tember. The species is known only from Mexico 
and Guanacaste Province in northwestern Costa 
Rica. 

Sebastiania pavoniana is recognized by its de- 
ciduous forest habitat, lack of pubescence, small 
leaves, small leaf-opposed or terminal inflores- 
cences, and minute $ flowers subtended by broadly 
sessile bracts. Stinging hairs are often present near 
the flowers. The minute glands at the apex of the 
sulcate petiole are useful in determining sterile col- 
lections. Specimens of this species had been in- 
correctly identified as Gymnanthes lucida (in herb.), 
Stillingia sp. and Ophellantha spinosa Standl. 
(Standley, 1 938, p. 1557). This is one of the species 
whose fruit, when inhabited by a larva, are called 
"jumping beans" (Mabberley, 1987). 

Skutchia caudata Pax & K. Hoffm., proposed 
as a new genus and species of Euphorbiaceae, is a 
synonym of Trophis mexicana (Liebm.) Bureau of 
the Moraceae. 

Stillingia Garden ex. Linnaeus 

Shrubs, small trees, or perennial (rarely annual) herbs, 
monoecious (bisexual), stems glabrous; stipules usually 



filiform and glandular or reduced. Leaves simple, alter- 
nate, opposite or whorled, petiolate, often with 2-3 cy- 
athiform or scutelliform glands at the apex of the petiole 
or base of blade; leaf blades glandular serrate, glabrous, 
venation pinnate. Inflorescences terminal or leaf-op- 
posed (axillary), solitary, bisexual or $, spiciform with a 
thick rachis (often with short basal lateral branches) gla- 
brous, bracts small, broadly sessile with 2 prominent 
lateral glands; 2 flowers proximal, 1 /bract, sessile; 6 flow- 
ers distal, 1-1 5/bract, subsessile. Male flowers glabrous, 
calyx 2-lobed, membranous, corolla and disk absent; 
stamens 2 (3), exserted, filaments free but united at the 
base, anthers longitudinally dehiscent and extrorse; pis- 
tillode absent. Female flowers glabrous, calyx usually of 
3 separate sepals (reduced or absent), corolla and disk 
absent, staminodes absent; ovary (2-)3-locular, ovules 
1/locule, styles connate at base, simple. Fruits capsules, 
usually 3-lobed and splitting into 3 2-valved capsules, 
columella absent but a 3-horned woody gynobase per- 
sisting after dehiscence; seeds subglobose, with or with- 
out caruncles, seed surface smooth or rugose. 

A genus of 25-30 tropical and warm-temperate 
species with centers of diversity in Mexico and 
Brazil, with a few additional species in the Mas- 
carene Islands, Malaysia, and Fiji. The lack of 
hairs, thick spikes, and leaves with glandular-ser- 
rate margins help distinguish the genus. Stillingia 
differs from Sapium in the smaller size of the plants, 
separate $ sepals (or none), hard seed testa, and 
glands of the leaves that are less prominent and 
not cylindrical. The genus is known in southern 
Central America from only two collections of the 
following species. 



Stillingia zelayensis (H.B.K.) Mull. Arg., Linnaea 
32: 87. 1863. Sapium zelayensis H.B.K., Nov. 
gen. sp. (quarto ed.) 2: 65. 1817. Stillingia mi- 
crosperma Pax. & K. Hoffm., Pflanzenreich 2, 
147, 5: 187. 1912. Figure 23. 

Shrubs 0.5-2 m tall, often with many distal branches, 
leafy stems 1.2-4.5 m thick, terete; stipules 0.3-1 mm 
long or absent, filiform, minutely triangular or broadly 
rounded and flat to 1 .2 mm diam. Leaves alternate, op- 
posite or whorled (often on the same branchlet), petioles 
2-10(-14) mm long, 0.4-1.2 mm thick, glabrous, with 
2-3 discoid, cupulate or patelliform glands at the apex 
or lamina base, ca. 0.5 mm high, 0.3-1.3 mm diam.; 
leaf blades (2.5-)3-8(-l 1) cm long, 0.7-3(-4) cm wide, 
narrowly elliptic to narrowly ovate-elliptic or elliptic- 
oblong, apex acute to acuminate, margin with slender 
(0.1-0.2 mm) gland-tipped teeth 0.2-0.8 mm long, ca. 
10-15 teeth/cm, base acute, drying stiffly chartaceous 
and often dark above, glabrous, 2 veins 6-14/side. In- 
florescences 4-16 cm long, simple and spiciform or with 
short (4 mm) proximal lateral branches, glabrous, pe- 
duncles 6-36 mm long, 1.5-3 mm thick, distal spike 3- 
6 mm wide, bracts to 2 mm long, broad at the base, 
often obscured by the large flat rounded to saddle-shaped 
glands 1-2.4 mm wide, flowers subsessile or short (1-2 



BURGER & HUFT: FLORA COSTARICENSIS 



157 



mm) pedicellate. Male flowers in glomerules of 7-1 1 
closely congested flowers, calyx ca. 1.3 mm long; fila- 
ments 1-1.5 mm long, anthers ca. 0.4 long and 0.8 mm 
wide. Female flowers with sepals ca. 3 mm long; ovary 
ca. 3 mm long, styles recurved. Fruits 8-12 mm long, 
to 15 mm wide, persisting woody gynobase 7-11 mm 
wide, with 3 acute lateral projections; seeds 5-7 mm 
long, 4.5-6 mm wide, ca. 4 mm thick, smooth and lus- 
trous, caruncle ca. 1.5 mm wide. 

Plants of open semideciduous vegetation, 1 000- 
2000 m elevation. Flowering in May-July in 
northern Central America. The species ranges from 
Mexico to Honduras and is known only from two 
collections in western Panama. 

Stillingia zelayensis is recognized by the small 
shrubby habit, lack of hairs, small leaves with 
prominent glands at the base of the blade, and 
spiciform inflorescences with thick rachis and ses- 
sile glomerules of $ flowers. It appears that the 
Panamanian collections represent a disjunct pop- 
ulation since this species has not been collected in 
Nicaragua or Costa Rica. 



Synadenium Boissier 

Shrubs and small trees, monoecious or dioecious, dis- 
tal stems fleshy and terete, sap white; stipules represented 
by small glands. Leaves alternate, simple, petiolate, blades 
semisucculent and entire. Inflorescences axillary or ter- 
minal, pedunculate, panicles or umbels of flower-like 
cyathia in dichotomizing cymes, each cyathium sub- 
tended by 2 bracts. Cyathium radially symmetrical, with 
a cup-shaped or saucer-like involucre, with a spreading 
or rim-like gland around the periphery of the involucre, 
with 5 thin subquadrate lobes within. Male flowers in 5 
groups opposite the lobes of the involucre, surrounded 
by membranous fringed-toothed lobes. Female flowers 
present or absent in the center of the cyathium, sepals 
reduced to a rim or of 3 lobes, ovary 3-locular, ovules 
1/locule, styles 3 united near base, bifid distally. Fruits 
capsular; seeds minutely carunculate. 

A genus of 1 3-1 9 species of eastern and southern 
Africa. One species is planted in gardens in Central 
America. For a more detailed discussion of the 
cyathium, see Euphorbia. 



Synadenium grantii Hook, f., Bot. Mag. t. 5633. 
1867. 

Shrubs or small trees to 3(-10) m tall, with few thick 
erect branches, stems succulent, leafy branchlets 3-10 
mm thick, terete, glabrous. Leaves with petioles merging 
with the decurrent leaf bases; leaf blades 5-17 cm long, 



2-6 cm wide, narrowly obovate to oblong-obovate or 
oblanceolate, apex obtuse, margin entire or minutely 
denticulate, base cuneate, green or often reddish beneath, 
glabrous except along the margins or near the base, 2 
veins 9-14/side, strongly ascending. Inflorescences 1.5- 
1 cm long, red or green, peduncles to 5 cm long, branch- 
ing dichotomous, bracts below the cyathium ca. 3 mm 
long; cyathia ca. 4 mm diam. 

Garden ornamentals cultivated for their short 
few-branched habit and succulent leaves; origi- 
nally from eastern and central Africa. Common 
names are bitamo, Bitamo-zapatillo, and "African 
milk bush." 



Tetrorchidium Poeppig 

Trees or shrubs, dioecious (monoecious), stems with 
simple hairs or hairs attached at the middle; stipules 
paired, often glandular along the lateral margins. Leaves 
alternate (opposite), simple, petiolate, prominent paired 
glands often present at or near the apex of the petiole, 
blades entire or dentate, venation pinnate. Male inflo- 
rescences axillary, spiciform (racemiform) or sometimes 
branched, flowers usually 3-7 in sessile glomerules; <3 
flowers small and subsessile, calyx lobes 3, imbricate in 
bud, opening early, ribbed on the inner (adaxial) face, 
petals and disk absent; stamens 3, opposite the calyx 
lobes, free, filaments usually very short, equal, anthers 
peltate and rounded, 4-thecous; pistillode small or ab- 
sent. Female inflorescences axillary, short racemes (or 
branched panicles), solitary; 9 flowers subsessile or ped- 
icellate, calyx lobes 3, petals absent, staminodia absent, 
disk cupulate or 3-lobed and narrow or broad; ovary 
with 2-3 locules, ovules 1/locule, styles short, free, bifid, 
often with broad stigma-like style branches. Fruits cap- 
sular, thin-walled, 2- or 3-lobed; seeds rounded, carun- 
cule absent (present), outer seed coat fleshy, inner coat 
foveolate, endosperm present, cotyledons broad and flat. 

A genus of ca. 20 American and 5 African spe- 
cies. The anthers, borne on very short filaments 
and with four separate thecae, form an androeci- 
um in which it is difficult to distinguish three sta- 
mens. The broad stylar branches form thick lobes 
that often cover the entire apex of the young ovary. 
Note that the thin erect disk of the 9 flower, wheth- 
er as three narrow elements or an entire cup, can 
be mistaken for a reduced corolla whorl. The hairs 
are often attached at the center, but this may be 
difficult to see. There is considerable variation 
within species, and this can make determination 
of individual collections difficult (cf. Webster & 
Huft, 1988). Two of our species can exceed 30 m 
in height. 



158 



FIELDIANA: BOTANY 



Key to the Species of Tetrorchidium 



la. Shoot apices and young stems glabrous [petioles usually with flat glands near the middle or in the 
distal half; disk represented by 3 narrow petal-like elements in 2 flowers, 2 flowers pedicellate, 0- 

1200 m, Mexico to Costa Rica] T. rotundatwn 

Ib. Shoot apices and young stems puberulent to strigose 2 

2a. Glands usually near the middle of the petiole [disk of the 2 flower represented by 3 slender segments; 

1200-1 700 m elevation] T. costaricensis 

2b. Glands usually near the apex of the petiole or at the base of the leaf blade 3 

3a. Leaf blades 2.7-7 cm long, 1-2 cm wide; plants of the Chiriqui Highlands at 1900-2300 m 

T. microphyllum 

3b. Leaf blades 9-25 cm long, 4-15 cm wide; Costa Rica and Panama at 20-1200 m elevation 

T. euryphyllum 



Tetrorchidium costaricense Huft, Ann. Missouri 
Bot. Gard. 75: 1112. 1988. Figure 21. 

Trees 8-16 m tall, older stems often with raised leaf 
scars, leafy stems 2.3-8 mm thick, with straight or crook- 
ed thin whitish hairs to 0.8 mm long; stipules 1.5-2.5 
mm long, 1.3-1.8 mm wide at base, triangular, pubes- 
cent, often becoming thickened at the base after leaf fall. 
Leaves with petioles 1.5-6 cm long, 0.7-1.8 mm thick, 
glabrous or minutely strigulose, paired glands 0.3-1 mm 
high, 0.5-1 mm diam., opposite or subopposite and lat- 
eral near the midpoint of the petiole; leaf blades (5-) 7- 
18 cm long, 2.5-7 cm wide, narrowly elliptic to elliptic- 
lanceolate, narrowly elliptic-obovate or obovate, tip acu- 
minate or caudate-acuminate, tip 5-10 mm long, margin 
entire, base acute to cuneate, drying chartaceous and 
dark green, sparsely pubescent with thin straight or 
V-shaped hairs 0.3-0.8 mm long, upper surface glabres- 
cent, 2 veins 5-7/side, arcuate-ascending. Male inflo- 
rescences 2-12 cm long, spiciform or paniculiform with 
lateral branches to 3 cm long, rachis pubescent, bracts 
ca. 1.5 x 1.5 mm, broadly sessile, glomerules sessile or 
on peduncles to 2 mm long, with 2-5 flowers; <5 flowers 
2-3 mm wide, sepals obovate, cucullate, glabrous exter- 
nally, pilose within, stamens subsessile, anthers 0.7-0.9 
mm long, ca. 1 mm wide, rounded. Female inflores- 
cences 1-5 cm long, usually spiciform, rachis sparsely 
puberulent, pedicels to 3 mm long in fruit (flowers at 
first subsessile); $ flowers ca. 2.5 mm long, calyx 1.5-2 
mm long, lobes ca. 0.5 mm long, triangular, glabrous 
externally, disk segments free, ca. 2 mm long and nar- 
rowly ligular, ovary smooth, stigmas 0.5-0.8 mm high, 
1.4-1.8 mm diam. (at first wider than the ovary), flat- 
tened distally. Fruits 4-6 mm long, 6-9 mm wide, oblate, 
2-3-lobed; seeds 4-6 mm long, ca. 5 mm wide, ovoid, 
reddish and with wrinkled surface (dried). 

Plants of montane evergreen rain forest for- 
mations, 1200-2000 m elevation. Flowers have 
been collected in March-April and November- 
January; fruiting in May-October. The species 
ranges from the Cordillera de Tilaran to western- 
most Panama. 

Tetrorchidium costaricense is recognized by its 
lower montane evergreen cloud forest habitat, pu- 



bescent stems, prominent paired glands near the 
middle of the petiole, and slender disk elements 
in the 2 flower. The small hairs attached at the 
center are distinctive, but their attachment is dif- 
ficult to see. 



Tetrorchidium euryphyllum Standl., Publ. Field 
Columb. Mus., Bot. Ser. 4: 219. 1929. Figures 
20 and 21. 

Trees 6-30 m tall, trunks 10-75 cm diam., sap whitish, 
leafy stems 3-9 mm thick, pubescent with thin straight 
appressed hairs 0.2-0.6 mm long; stipules 0.5-1.5 mm 
long, often obscure. Leaves with petioles (l-)2-6.5 cm 
long, 1-3.3 mm thick, minutely appressed-puberulent, 
with paired rounded/tubular glands ca. 1 mm long on 
the abaxial lamina margins above the petiole apex; leaf 
blades 10-26 cm long, 4-1 5 cm wide, elliptic to broadly 
elliptic or broadly elliptic-obovate, apex often abruptly 
narrowed and usually short-acuminate, margin entire or 
slightly dentate with few (3-7/side) sessile cupuliform 
glands 0.3-0.6 mm diam., base cuneate to obtuse and 
slightly decurrent on the petiole, drying stiffly charta- 
ceous and often yellowish green or yellowish brown, with 
minute (0.3 mm) appressed straight hairs attached at the 
center, 2 veins (3-)5-8/side, prominent beneath, distal 
veins arcuate-ascending. Male inflorescences often 3/axil, 
3-12 cm long, spike-like or racemiform (rarely panicu- 
late with lateral branches to 20 mm long), glomerules 
sessile or pedunculate, rachis 0.7-1 mm thick, pubescent 
with yellowish hairs, bracts 1-1.5 mm long, broadly ses- 
sile, minutely (0.2-0.5 mm) pubescent, each with 2 
rounded flat lateral glabrous glands 0.6-1.2 mm diam., 
subtending 1-3 flowers; 6 flowers with 3 anthers sessile 
on a short (0.3-0.7 mm) thick column. Female inflores- 
cences 1-2/axil, to 5 cm long, rachis 0.6-1 mm thick, 
pubescent, flowers solitary and distant, subsessile (some- 
times pedicellate in fruit); 9 flowers with calyx 1-1.5 mm 
long, calyx lobes 3, cupular disk 0.3-1 mm high, thin 
and resembling a corolla cup, ovary 1-1.5 mm long, 
ovoid, subglabrous, stigmas sessile, 0.7-1 mm wide dis- 
tally. Fruits 3-4 mm long, 5-6 mm wide, oblate and 2- 
or 3-lobed, green, columella ca. 3 mm long, rarely per- 
sisting; seeds ca. 4 x 3 mm, seed coat reddish. 



BURGER & HUFT: FLORA COSTARICENSIS 



159 



Plants of evergreen rain forest formations of the 
Caribbean slope and central highlands, 50-1000 
m elevation (to 1 200 m near Fortuna Dam in Chi- 
riqui). Flowering in December-May and July; 
fruiting in March-July. The species ranges from 
the Caribbean slope of northern Costa Rica to 
northern Colombia. 

Tetrorchidium euryphyllum is recognized by its 
larger entire or slightly dentate leaves with two to 
four glands along the decurrent base of the lamina 
(sometimes at the apex of the petiole). These glands 
are sometimes erect and cylindrical with a round 
distal opening (urn-like). In addition, the ovary is 
partly enclosed in a cupulate corolla-like disk, and 
the lateral glands of the floral bracts are often as 
large or larger than the bracts themselves. The 
slender hairs are distinctive because they are at- 
tached at the center, but this is often difficult to 
see. This species is similar to T. gorgonae Croizat 
of Panama and Colombia, but that species has 
smaller leaves with narrow petiolar glands, fewer 
2 veins and pedicellate 9 flowers. 

Tetrorchidium microph yllum Huft, Ann. Missouri 
Bot. Gard. 75: 1110. 1988. 

Small usually slender trees 6-1 m tall, distal branches 
with raised knobby leaf scars, leafy stems 1.2-4 mm 
thick, densely strigulose with yellowish hairs ca. 1 mm 
long; stipules 0.5-2 mm long, triangular, strigulose, be- 
coming thickened and glabrous at the base after leaf fall. 
Leaves clustered near the ends of stems, petioles 5-16 
mm long, 0.6-1.2 mm thick, sparsely puberulent, gla- 
brescent, yellowish, with 2 opposite/subopposite cylin- 
drical or cupuliform glands near the apex, 0.5-0.8 mm 
diam .; leaf blades 2.7-7 cm long, 0.9-2 cm wide, oblan- 
ceolate to narrowly elliptic-oblanceolate or narrowly el- 
liptic, apex acuminate, margin entire, base gradually nar- 
rowed and acute or cuneate, drying stiffly chartaceous, 
yellowish, at first minutely strigulose with appressed hairs 
0.2-0.3 mm long, glabrescent, 2 veins 4-5/side. Male 
inflorescences 1-3 cm long, spiciform, rachis ca. 0.6 mm 
thick, strigulose with short (0.3 mm) yellowish hairs, 
bracts 1-1.5 mm long, broadly sessile, mostly glabrous; 
6 flowers 1.5 mm wide, calyx lobes 0.7-1.2 mm long, 
triangular, anthers ca. 0.7 mm wide, anthers subsessile, 
0.8-0.9 mm long. Female inflorescences, flowers and 
fruits unknown. 

Plants of evergreen cloud forests, 1900-2300 m 
elevation. Flowers were collected in February 
(Hammel 6039) and November (Hammel 5721, 
the type). The species is known only from north- 
east of Boquete, Chiriqui Province, Panama. 

Tetrorchidium microphyllum is recognized by 
its restricted higher-elevation habitat and smaller 
narrow glabrescent leaves. The distal stems below 
the leaves are conspicuously knobby, due in part 



to the enlargement of the lateral bases of the stip- 
ules. 



Tetrorchidium rotundatum Standl., Trop. Woods 
16: 44. 1928. Figure 21. 

Trees 8-35 m tall, larger trees often with buttresses, 
distal stems with prominent leaf scars, leafy stems 3-9 
mm thick, glabrous and often lustrous, yellowish, be- 
coming knobby; stipules ca. 1.3 x 1.3 mm, triangular, 
persisting and becoming thickened after leaf fall. Leaves 
with petioles 25-60 mm long, 1 .4-3 mm thick, glabrous, 
paired lateral glands usually present near the middle of 
the petiole, flat, 0.5-0.7 mm wide, 0.2-0.4 mm high; leaf 
blades 9-26 cm long, 3.5-10 cm wide, elliptic to nar- 
rowly elliptic-oblong or elliptic-oblong, apex bluntly ob- 
tuse to subacuminate, margin entire or slightly undulate 
(glands along the margin minute), gradually narrowed to 
the cuneate base, drying chartaceous and dark green or 
yellowish green, glabrous, 2 veins 6-8/side, flat beneath, 
ascending. Male inflorescences 4-20 cm long, spiciform, 
rachis 0.7-0-1.5 mm thick, glabrous or sparsely puber- 
ulent distally, glomerules sessile with 3-7 flowers, bracts 
usually obscured by the flowers; $ flowers ca. 1 mm wide. 
Female inflorescences usually I/axil, 2-6 cm long, gla- 
brous at the base but rachis and pedicels densely pu- 
berulent, pedicels becoming 4-8 mm long in fruit, to 1 
mm thick; 2 flowers 2-3 mm long, calyx ca. 1 .5 mm long, 
lobes ca. 0.5 mm long, obtuse, exterior densely and mi- 
nutely (0.1-0.2 mm) puberulent, disk segments ca. 1 x 
0.3 mm, oblong; ovary ca. 1 mm diam., glabrous, stig- 
mas 0.3-0.6 mm thick, 1.3-1.5 mm wide, flattened dis- 
tally. Fruits 5-7 mm long, 8-1 1 mm wide, oblate and 
usually 2-lobed, columella not usually separating from 
both valves; seeds ca. 7 x 6 mm, with wrinkled reddish 
surface (dried). 

Plants of lowland evergreen forest formations, 
0-1 200 m elevation. Flowering in November-April 
and August; fruiting primarily in May-October. 
The species is known only from four collections 
in Costa Rica: Grayum & Herrera 4843 from ca. 
500 m elevation east of the Rio Tenorio, Oersted 
5819 from Monte Aguacate, Rivera 935 from P.N. 
Rincon de la Vieja, and Zuniga 250 from the Re- 
serva Biologica Carara with fruits in May. The 
species ranges from Veracruz, Mexico, to central 
Costa Rica. 

Tetrorchidium rotundatum is recognized by the 
lower elevation habitats, generally glabrous leaves 
and stems, the flat (not prominent) lateral glands 
usually in the distal half of the petiole, larger leaf 
blades, and pedicellate 9 flowers with narrow disk 
segments (resembling narrow petals). The 9 inflo- 
rescence, glabrous at the base and quickly becom- 
ing pubescent distally, is distinctive. This species 
is very similar to T. brevifolium Standl. & Steyerm. 
(including T. molinae L. Wms.) of northern Cen- 
tral America, but that species has smaller leaves, 



160 



FIELDIANA: BOTANY 



glabrous 2 inflorescences, and glands at the apex 
of the petiole and has not been collected from 
below 1200 m elevation. 



Tragia Linnaeus 

Herbs, vines, or shrubs, monoecious, hairs simple, of- 
ten stinging; stipules paired, entire or lobed, usually per- 
sisting. Leaves alternate, simple, petiolate, entire to ser- 
rate, sometimes deeply lobed, venation pinnate or pal- 
mate. Inflorescences opposite the leaves or terminal on 
short lateral branches (also axillary), usually solitary, 
mostly bisexual, simple or bifurcate, 2 flowers usually 
1 -several and proximal, 3 flowers many and alternate 
along the unbranched rachis, bracts small, subtending 
1-3 $ and solitary 2 flowers. Male flowers borne on ar- 
ticulated pedicels, sepals 3-6, valvate in bud, corolla and 
disk absent; stamens 2-5(-40), filaments free or united 



at the base, short, anthers dehiscing longitudinally; pis- 
tillode small or absent. Female flowers with pedicels of- 
ten elongating in fruit, sepals 3-6, imbricate; petals and 
disk absent; ovary usually 3-locular, hispid with stinging 
hairs, ovules 1/locule, styles 3, united at base, slender, 
undivided. Fruits capsules, often covered with stinging 
hairs, usually breaking into 3 2-valved cocci, columella 
persisting, with 3 broad wings at the apex; seeds subglo- 
bose, smooth or slightly ridged, ecarunculate, endosperm 
carnose, cotyledons broad flat. 

A tropical genus of ca. 125 species, mostly Af- 
rican and American. The herbaceous vining stems, 
stinging hairs, and unbranched or two-branched 
inflorescences arising from opposite the adjacent 
leaf base make our species quite distinctive. Poor 
representation of these plants in herbaria may be 
a reflection of their urticating pubescence and slen- 
der twining habit. 



Key to the Species of Tragia 

la. Leaves 8-26 cm wide, cordate at the base with a conspicuous sinus 15-20 mm deep; inflorescences 
bifurcate, rachis 1-3 mm thick; $ flowers with 30-^40 conspicuous stamens; evergreen Caribbean 
slope, 0-800(-1 500) m elevation T. bailloniana 

Ib. Leaves 1.7-6.5 cm wide, rounded and truncate to cordate at the base with a short (to 6 mm) sinus; 
inflorescences simple, rachis ca. 0.3 mm thick; $ flowers with 2 minute stamens; Meseta Central 
and Pacific slope, 0-1 300 m elevation 2 

2a. Pistillate flowers long-pedicellate, styles partly connate; stems herbaceous, often green or yellowish; 
plants of partly deciduous vegetation, 700-1300 m elevation in Costa Rica (0-1500 m elsewhere) 
T. volubilis 

2b. Pistillate flowers subsessile, styles free; stems slightly woody and often reddish brown; rarely collected 

plants of evergreen vegetation 20-500 m elevation in southern Costa Rica and Panama 

. T. correae 



Tragia bailloniana Miill. Arg., Linnaea 34: 178. 
1865, and in DC, Prodr. 15 (2): 927. 1866. 
Zuckertia cordata Baill., Etud. Euphorb. 496, p. 
4. 1858, not Tragia cordata Mich. Figures 2 
and 5. 



Herbaceous vines and climbers, 2-4(-6) m high, leafy 
stems 2-4 mm thick, with stiff straight to slightly curved 
stinging hairs to 2.5 mm long; stipules 7-13 mm long, 
lanceolate to narrowly ovate-triangular, acute. Leaves 
variable in shape on the same plant, petioles 6-12(-25) 
cm long, 1.3-2.7 mm thick, often thickened and genic- 
ulate at the base, with hairs 0.5-2.5 mm long; leaf blades 
13-33 cm long, 8-26 cm wide, unlobed and ovate to 
broadly ovate or prominently 3-lobed with sinuses 1-9 
cm deep, (rarely also with lateral basal lobes), apices 
acuminate with slender tip 5-22 mm long, margin with 
small (0.3-0.5 mm) teeth, \-4 teeth/cm, base cordate, 
basal sinus 1.5-5 cm deep, drying membranaceous and 
greenish, upper surface with straight slender stinging hairs 



0.7-2 mm long and minute hairs above the major veins, 
larger hairs to 1 .4 mm long beneath, venation palmate 
with 3 (5) major veins, 2 veins 3-5/side of the midvein, 
3 veins often subparallel. Inflorescences 5-13 cm long, 
usually bifid from a peduncle 1-10 cm long, 1.5-4 mm 
thick, branches unisexual, <5 racemes 5-13 cm long, bracts 
3-5 mm long, ovate-lanceolate and subglabrous, sub- 
tending 1-3 flowers, 2 axis to 18 cm long, spiciform, 2 
bracts 3-8 mm long, lanceolate, smaller distally. Male 
flowers borne on pedicels 8-10 mm long, ca. 0.2 mm 
thick, buds pyriform-obovoid, sepals usually 4, 6-7 mm 
long, 1.3-2 mm wide, oblanceolate, glabrous or ciliate 
on the margin, stamens 28-40, filaments 3-3.5 mm long 
united near the base in groups of ca. 3, anthers 0.7-1 
mm long. Female flowers borne on pedicels 1-4 mm 
long (hidden by bracts), hirsutulous, sepals 3-5 mm long, 
1.7-2.7 mm wide, lanceolate, mostly glabrous abaxially; 
ovary covered with stiff straight stinging hairs ca. 1 mm 
long, styles 6-9 mm long, 0.6-1.2 mm thick, separate 
distally for 2.5-4.5 mm. Fruits 8-13 mm long, 12-22 
mm wide, prominently 3-lobed, glabrescent, columella 
ca. 6 mm long, distal wings to 5 mm wide; seeds ca. 6 
mm long, subglobose. 



BURGER & HUFT: FLORA COSTARICENSIS 



161 



Plants of lowland evergreen rain forest forma- 
tions of the Caribbean slope, 10-800 m elevation 
(to 1500 m in Chiriqui). Probably flowering 
throughout the year (collected in September in 
Costa Rica). The species ranges from Veracruz, 
Mexico, to western Panama. 

Tragia bailloniana is distinguished by its slen- 
der climbing habit, large cordate leaves on long 
petioles, inflorescences with two long unbranched 
axes (1 $ and 1 9), and stinging hairs on many 
parts. The more deeply lobed leaves resemble those 
of Gurania (Cucurbitaceae), but the stinging hairs 
will quickly alert the unwary (compare also Dal- 
echampia shankii). Because of its distinctive fea- 
tures, this species is placed in the monotypic sec- 
tion Zuckertia (Baill.) Mull. Arg. 

Tragia correae Huft, Ann. Missouri Bot. Gard. 75: 
1107. 1988. Figure 5. 

Vines or slender lianas with brown or reddish brown 
stems, leafy stems ca. 2 mm thick, with both minute (0.2 
mm) and longer straight stinging hairs to 1.5 mm long; 
stipules 4-10 mm long, narrowly triangular to narrowly 
ovate, pilose. Leaves with petioles 25-65 mm long, 0.7- 
1 mm thick, with slender erect hairs 1-1.5 mm long; leaf 
blades 5-12 cm long, 2-6 cm wide, elliptic-oblong to 
oblong-triangular or narrowly oblong, apex acuminate 
or subacuminate, margin minutely denticulate with 1 5- 
30 teeth/side, base lounded and cordate to subcordate, 
sinus 3-6 mm deep, drying membranaceous, surfaces 
with straight hairs 0.2-0.8 mm long, venation pinnate 
or subpalmate, 2 veins 5-7/side. Inflorescences opposite 
the leaves, solitary, greenish yellow, 3-6 cm long (to 1 6 
cm after fruiting), rachis ca. 0.3 mm thick, pubescent, 2 
flower solitary and proximal, subtended by a 3-lobed 
bract, $ flowers 20-60, distal, subtended by bracts ca. 
2.5 x 1.3 mm, ovate-lanceolate and entire, margins cil- 
iate. Male flowers short-pedicellate, calyx lobes 3, ca. 
1.3 x 1.2 mm, obovate and acute, hispidulous exter- 
nally; stamens 3, free, filaments ca. 0.8 mm long, thick, 
anthers 0.2-0.3 mm long, elliptic, extrorse. Female flow- 
ers on pilose pedicels 2-4 mm long, calyx lobes 5, 2-3 
mm long, ca. 0.7 mm wide, lanceolate; ovary 2-3 mm 
diam.. densely hispidulous with stinging hairs, styles free, 
2-3 mm long, spreading, recurved. Fruits not seen at 
maturity. 

Plants of evergreen forests of the Pacific slope, 
40-600 m elevation. Flowering in January and 
September; with old inflorescences in November. 
This species is known only from near Sierpe, Pun- 
tarenas, in southern Costa Rica (Aguilar 872, Her- 
rera 4581 & 4784) and in the province of Panama, 
Panama (Sucre et al. 9832 the type). 



Tragia correae is recognized by its Pacific slope 
habitat, reddish brown slightly woody stems, 
stinging hairs, simple inflorescences, and oblong 
or somewhat triangular leaf blades shallowly cor- 
date at the base, thin and drying translucent. 

Tragia volubilis L., Sp. PI. 980. 1753. Figure 5. 

Herbaceous vines to 3 m high, stinging hairs present 
on stems and leaves, leafy stems 0.5-3 mm thick, with 
curved or straight slender hairs 0.3-1 mm long; stipules 
2-4 mm long, 0.7-1 mm wide at base, narrowly trian- 
gular, sparsely pubescent. Leaves with petioles 5-70 mm 
long, 0.4-1 mm thick, with stinging hairs 0.4-1 mm long; 
leaf blades 2.5-10 cm long, 1.7-5(-6.5) cm wide, ovate- 
triangular to triangular or oblong-triangular, apex acute 
to short-acuminate, margin with acute teeth 0.5-3 mm 
long (6-1 8 teeth/side), base rounded and cordate or trun- 
cated at 90 to the petiole, drying chartaceous, often 
much paler beneath than above, surfaces with straight 
slender hairs 0.3-1 .5 mm long, venation pinnate or sub- 
palmate, 2 veins 3-6/side. Inflorescences opposite the 
leaves or axillary, usually solitary, 2-5 cm long, $ flowers 
usually solitary and proximal, on a slender pedicel to 3 
cm long, subtended by a 3-parted bract 1-2 mm long, 
rachis ca. 0.3 mm thick, strigulose, <3 bracts 1-1.6 mm 
long, entire, alternate along the rachis, with 1 <5 flower, 
pedicels to 1 .6 mm long, slender and articulated below 
the middle, base persisting. Male flowers ca. 0.7 mm 
wide, sepals 3, 0.6-0.9 mm long, 0.4-0.6 mm wide, ovate; 
stamens 2, filaments thick, short, anthers 0.3-0.4 mm 
long, 0.1-0.2 mm wide. Female flowers with 6 sepals in 
2 series, 1.6-2.5 mm long, 0.4-1 mm wide (enlarging in 
fruit); ovary covered with stiff slender hairs ca. 1 mm 
long, styles 2.5 mm long, style column 0.5-1.5 mm long, 
branches recurved. Fruits ca. 4 mm long, ca. 6 mm wide 
(sometimes dimorphic) densely covered with sharp 
stinging hairs, borne on slender pedicels to 25 mm long, 
columella 1.4-2 mm long, with distal wings 1.7-2 mm 
wide; seeds 2.2-3 mm diam., subglobose, with irregular 
raised reddish ridges on a paler surface. 

Plants of deciduous or partly deciduous forests 
on the Pacific slope and around the Meseta Cen- 
tral, 20-1300 m elevation (to 1500 m in Guate- 
mala). Flowering and fruiting in April-December. 
The species ranges from Mexico and Cuba to Peru 
and Argentina; also widespread in tropical Africa. 

Tragia volubilis is recognized by its slender vin- 
ing habit, the often triangular and clearly serrate 
leaves, and small unisexual flowers. More impor- 
tant in recognition are its stinging hairs, which are 
found on most parts. Local names are pica-pica 
(Costa Rica), chichicaste de raton (Guatemala), and 
chimbra (Nicaragua). 



162 



FIELDIANA: BOTANY 



Literature Cited 

ALLEN, P. 1956. The Rain Forests of Golfo Dulce. 

University of Florida Press, Gainesville, 4 1 7 pp. 
ARMBRUSTER, W. S. 1988. A new species, section and 

synopsis of Dalechampia (Euphorbiaceae) from Costa 

Rica. Syst. Bot., 13: 303-312. 
COBLEY, L. S., AND W. M. STEELE. 1976. The Botany 

of Tropical Crops. Longmans, New York, 357 pp. 
CORRELL, D. S., AND H. B. CORRELL. 1982. Flora of 

the Bahama Archipelago. J. Cramer, Vaduz, 1 ,692 pp. 
CROAT, T. B. 1978. Flora of Barro Colorado Island. 

Stanford University Press, Stanford, California, 943 

PP. 
GILLESPIE, L. J. 1993. Euphorbiaceae of the Guianas; 

annotated species checklist and key to the genera. Brit- 

tonia, 45: 56-94. 
INGRAM, J. 1980. The generic limits of Argythamnia 

(Euphorbiaceae). Gent. Herb., 11: 427-436. 
MABBERLEY, D. J. 1987. The Plant Book. Cambridge 

University Press, Cambridge, 706 pp. 
McVAUGH, R. 1993. Euphorbiae Novo-Galicianae re- 

visae. Contr. Univ. Michigan Herb., 19: 207-239. 
OPLER, P. A., G. W. FRANKIE, AND H. G. BAKER. 1976. 

Rainfall as a factor in the release, timing and syn- 
chronization of anthesis by tropical trees and shrubs. 

J. Biogeogr., 3:231-236. 



PTTTIER, H. A. 1957. Ensayo sobre Plantas Usuales de 
Costa Rica, 2nd ed. rev. Editorial Universitaria, San 
Jose, Costa Rica, 264 pp. 

STANDLEY, P. C. 1937. Euphorbiaceae. In Flora of Cos- 
ta Rica. Publ. Field Mus. Nat. Hist., Bot. Ser., 18: 
598-622. 

STANDLEY, P. C., AND J. A. STEYERMARK. 1949. Eu- 
phorbiaceae. In Flora of Guatemala. Fieldiana Bot., 
24(6): 25-170. 

WEBSTER, G. L. 1 987. The saga of the spurges: A review 
of classification and relationships in the Euphorbiales. 
Bot. J. Linn. Soc., 94: 3^6. 

WEBSTER, G. L. 1 994a. Classification of the Euphor- 
biaceae. Ann. Missouri Bot. Gard., 81: 3-32. 

WEBSTER, G. L. 1 994b. Synopsis of the genera and 
suprageneric taxa of Euphorbiaceae. Ann. Missouri 
Bot. Gard., 81: 33-144. 

WEBSTER, G. L., AND D. BURCH. 1967 (1968). Eu- 
phorbiaceae. In Woodson, R. E., and R. W. Schery, 
Flora of Panama. Ann. Missouri Bot. Gard., 54: 21 1- 
350. 

WEBSTER, G. L., AND M. J. HUFT. 1988. Revised syn- 
opsis of Panamanian Euphorbiaceae. Ann. Missouri 
Bot. Gard., 75: 1087-1144. 

WEBSTER, G. L., AND L. J. POVEDA. 1978. A phyto- 
geographically significant new species ofJatropha (Eu- 
phorbiaceae) from Costa Rica. Brittonia, 30: 265-270. 



BURGER & HUFT: FLORA COSTARICENSIS 



163 



List of Accepted Species 

Key: CULT = cultivated; END = endemic to Costa Rica; CR + WP = endemic to Costa Rica and 
western Panama; WP = endemic to western Panama; ?? = not collected in Costa Rica but known from 
nearby areas. The treatment includes 188 species, of which 150 are native or naturalized and 23 are 
cultivated. Those endemic to Costa Rica number 1 0, with 7 additional species endemic to Costa Rica 
and western Panama. Fifty-two genera are included, of which 45 are native. 



Acalypha alopecuroides 
Acalypha amentacea ssp. wilke- 

siana CULT 

Acalypha apodanthes END 
Acalypha arvensis 
Acalypha costaricensis 
Acalypha diversifolia 
Acalypha ferdinandii 
Acalypha hispida CULT 
Acalypha leptopoda 
Acalypha macrostachya 
Acalypha mexicana 
Acalypha obtusifolia ?? 
Acalypha polystachya 
Acalypha radinostachya 
Acalypha schiedeana 
Acalypha septemloba CR + WP 
Acalypha setosa 
Acalypha triloba 
Acalypha villosa 
Acalypha sp. aff. A. mortoniana 
Acidoton nicaraguensis 
Actinostemon caribaeus 
Adelia triloba 
Adenophaedra grandifolia 
Alchornea costaricensis 
Alchornea glandulosa 
Alchornea grandiflora 
Alchornea latifolia 
Alchornea triplinervia 
A Ichorneopsis floribunda 
Aleurites fordii CULT 
Aleurites moluccana CULT 
Amanoa guianensis 
Ant ides mia bunius CULT 
Aparisthmium cordatum 
Argythamnia guatemalensis 
Astrocasia tremula 



Bernardia macrophylla 
Bernardia nicaraguensis 
Breynia disticha CULT 



Caperonia castaneifolia 
Caperonia palustris 
Caryodendron angustifolium CR + 

WP 

Chamaesyce bahiensis 
Chamaesyce bombensis 
Chamaesyce densiflora 
Chamaesyce dioeca 
Chamaesyce hirta 
Chamaesyce hypericifolia 



Chamaesyce hyssopifolia 
Chamaesyce lasiocarpa 
Chamaesyce mesembryanthemi- 

folia 

Chamaesyce nutans 
Chamaesyce ophthalmica 
Chamaesyce prostrata 
Chamaesyce serpens 
Chamaesyce thymifolia 
Cleidion castaneifolium 
Cnidoscolus aconitifolius CULT 
Cnidoscolus tubulosus 
Cnidoscolus urens 
Codiaeum variegatum CULT 
Conceveiba pleiostemona 
Croton argenteus 
Croton axillaris 
Croton billbergianus 
Croton brevipes 
Croton decalobus 
Croton draco 
Croton glandulosus ?? 
Croton hirtus 
Croton hoffmannii END 
Croton jimenezii END 
Croton jutiapensis 
Croton lanjouwensis 
Croton lobatus 
Croton mexicanus 
Croton niveus 
Croton ortholobus END 
Croton ovalifolius 
Croton pachypodus 
Croton punctatus 
Croton pungens WP 
Croton schiedeanus 
Croton skutchii END 
Croton smithianus 
Croton speciosus 
Croton sphaerocarpus 
Croton tenuicaudatus CR + WP 
Croton tonduzii END 
Croton trinitatis 
Croton xalapensis 
Croton yucatanensis 
Croton sp. aff. C. yucatanensis END 



Dalechampia arenalensis END 
Dalechampia canescens ?? 
Dalechampia cissifolia 
Dalechampia dioscoreifolia 
Dalechampia heteromorpha 
Dalechampia osana END 
Dalechampia scandens 



Dalechampia shankii 
Dalechampia spathulata 
Dalechampia tiliifolia 
Dalechampia websteri CR + WP 
Drypetes brownii 
Drypetes lateriflora 
Drypetes sp. aff. D. alba 
Drypetes standleyi 
Dysopsis glechomoides 



Euphorbia colletioides 
Euphorbia cotinifolia CULT 
Euphorbia cyathophora 
Euphorbia dwyeri CR + WP 
Euphorbia elata 
Euphorbia graminea 
Euphorbia heterophylla 
Euphorbia hoffmanniana END 
Euphorbia leucocephala CULT 
Euphorbia neriifolia CULT 
Euphorbia ocymoidea 
Euphorbia oerstediana 
Euphorbia peplus CULT 
Euphorbia pulcherrima CULT 
Euphorbia schlechtendalii 
Euphorbia segoviensis 
Euphorbia splendens CULT 
Euphorbia tirucalli CULT 
Euphorbia xalapensis 



Garcia nutans 
Gymnanthes lucida T! 
Gymnanthes riparia 



Hevea brasiliensis CULT 
Hippomane mancinella 
Hura crepitans 
Hyeronima alchorneoides 
Hyeronima oblonga 

Jatropha costaricensis END 
Jatropha curcas 
Jatropha gossypiifolia 
Jatropha integerrima CULT 
Jatropha multifida CULT 
Jatropha podagrica CULT 



Mabea excelsa 
Mabea occidentalis 
Manihot aesculifolia 



164 



FIELDIANA: BOTANY 



Manihot brachyloba 
Manihot esculenta CULT 
Manihot glaziouvii CULT 
Margaritaria nobilis 



Omphalea diandra 



Pausandra trianae 
Pedilanthus tithymaloides CULT 
Pera arborea 

Phyllanthus acidus CULT 
Phyllanthus acuminatus 
Phyllanthus amarus 
Phyllanthus caroliniensis 
Phyllanthus compressus ?? 
Phyllanthus hyssopifolioides 
Phyllanthus mocinianus 



Phyllanthus niruri 
Phyllanthus salviifolius 
Phyllanthus skutchii END 
Phyllanthus stipulatis 
Phyllanthus urinaria 
Phyllanthus valerii 
Plukenetia penninervia 
Plukenetia stipellata 



Richeria obovata 
Ricinus communis CULT 



Sagotia racemosa 
Sapium allenii END 
Sapium glandulosum 
Sapium laurifolium 
Sapium macrocarpum 



Sapium pachystachys 
Sapium rigidifolium END 
Sapium thelocarpum 
Sebastiania corniculata ?? 
Sebastiania panamensis WP 
Sebastiania pavoniana 
Stillingia zelayensis WP 
Synadenium grantii CULT 



Tetrorchidium costaricense 
Tetrorchidium euryphyllum 
Tetrorchidium microphyllum CR + 

WP 

Tetrorchidium rotundatum 
Tragia bailloniana 
Tragia correae CR + WP 
Tragia volubilis 



BURGER & HUFT: FLORA COSTARICENSIS 



165 



Index 

The index includes all accepted names (in Roman type), synonyms (italics), common English names 
(Roman), and vernacular Spanish names (italics). Page numbers of illustrations are in boldface. The text 
does not include new names or combinations. 



Acalypha 46 

subgenus Linostachys 50 
Acalypha alopecuroides 24, 48 
Acalypha amentacea 48 

subsp. wilkesiana 48 
Acalypha apodanthes 27, 49 
Acalypha arvensis 24, 49 
Acalypha costaricensis 28, 50 
Acalypha diversifolia 27, 50 
Acalypha ferdinandii 27, 5 1 

var. pubescens 49 
Acalypha fertilis 52 
Acalypha hicksii 52 
Acalypha hispida 5 1 
Acalypha indica 52, 53 

var. mexicana 52 
Acalypha irazuensis 54 
Acalypha lotsii 5 1 
Acalypha leptopoda 5 1 
Acalypha leptostachya 28, 50 
Acalypha macrostachya 28, 52 
Acalypha mexicana 24, 52 
Acalypha mortoniana 56 
Acalypha obtusifolia 53 
Acalypha panamensis 50 
Acalypha pittieri 53 
Acalypha polystachya 53 
Acalypha radinostachya 53 
Acalypha schiedeana 27, 54 
Acalypha seemannii 52 
Acalypha septemloba 27, 54 
Acalypha setosa 54 
Acalypha sp. aff. A. mortoniana 56 
Acalypha tabascensis 50 
Acalypha triloba 55 
Acalypha unibracteata 52 
Acalypha villosa 28, 55 
Acalypha wilkesiana 48 
Acidocroton spinosus 138 
Acidoton 56 

Acidoton nicaraguensis 25, 56 
Acidoton venezuelensis 57 
aceito de castor \ 50 
aceito de ricino 1 50 
aceite de pal ma- Christ i 150 
Actinostemon 57 
Actinostemon brachypodus 58 
Actinostemon caribaeus 38, 57 
Actinostemon concolor 58 
Actinostemon concolor 

var. caribaeus 57 
Adelia 58 

Adelia barbinervis 59 
Adelia triloba 44, 58 
Adenopetalum boerhaaviifolium 1 1 7 
Adenopetalum discolor 1 1 7 
Adenopetalum hoffmannii 1 1 7 
Adenopetalum irasuensis 117 
Adenopetalum pubescens 1 1 7 



Adenopetalum subsinuatum 1 1 7 
Adenophaedra 59 
Adenophaedra grandifolia 26, 59 
african milk bush 158 
Aklema colletioides 1 16 
Alchornea 59 
Alchornea costaricensis 25, 60 

f. longispicata 60 
Alchornea cydophylla 6 1 
Alchornea glandulosa 37, 6 1 

var. floribunda 63 

var. pittieri 6 1 
Alchornea grandiflora 6 1 
Alchornea guatemalensis 62 
Alchornea latifolia 37, 6 1 
Alchornea macrophylla 65 
Alchornea oblongifolia 80 
Alchornea pittieri 6 1 
Alchornea platyphylla 6 1 
Alchornea triplinervia 62 
Alchorneopsis 62 
Alchorneopsis floribunda 37, 63 
Aleurites 63 
Aleurites fordii 63 
Aleurites moluccana 64 
Aleurites montana 64 
Aleurites tribola 64 
Amanoa 64 

Amanoa guianensis 40, 65 
Amanoa macrocarpa 65 
Amanoa potamophila 65 
Anisophyllum bahiensis 73 
Anisophyllum densiflorum 74 
Antidesma 127 
Antidesma bunius 65 
Antidesma triplinervia 62 
Aparisthmium 65 
Aparisthmium cordatum 33, 65 
Argythamnia 66 

Argythamnia guatemalensis 24, 66 
Astraea seemannii 93 
Astrocasia 67 
Astrocasia peltata 67 
Astrocasia phyllanthoides 67 
Astrocasia tremula 45, 67 
Ateramnus lucidus 1 24 
Averrhoa acida 142 

barrabds 116 
beefsteak plant 49 
Bernardia 68 
Bernardia denticulata 59 
Bernardia grandifolia 59 
Bernardia macrophylla 25, 68 
Bernardia nicaraguensis 25, 68 
bitamo 139, 158 
bitamo real 1 39 
bitamo zapatillo 158 
Breynia 69 



Breynia disticha 69 

f. nivosa 69 
Breynia nivosa 69 

campano 97 
cancho de Brazil 125 
capa del rey 49 
Caperonia 69 
Caperonia angusta 70 
Caperonia castaneifolia 23, 70 
Caperonia paludosa 70 
Caperonia palustris 23, 70 

var. lineahfolium 70 
Caperonia panamensis 70 
Caperonia stenomeres 70 
Caryodendron 71 
Caryodendron angustifolium 7 1 
Caryodendron orinocensis 7 1 
cassava 136 
castor oil plant 1 50 
Chamaesyce 71 

Chamaesyce ammannioides 74 
Chamaesyce bahiensis 20, 73 
Chamaesyce bombensis 19, 74 
Chamaesyce buxifolia 77 
Chamaesyce densiflora 20, 74 
Chamaesyce dioeca 19, 75 
Chamaesyce dioica 75 
Chamaesyce glomifera 76 
Chamaesyce hirta 20, 75 
Chamaesyce hypericifolia 76 
Chamaesyce hyssopifolia 20, 76 
Chamaesyce lasiocarpa 20, 77 
Chamaesyce mesembryanthemifol- 

ia 20, 77 

Chamaesyce nutans 20, 77 
Chamaesyce opthalmica 19, 78 
Chamaesyce prostrata 19, 78 
Chamaesyce serpens 19, 79 
Chamaesyce thymifolia 19, 79 
chenile plant 5 1 
chame 82 

chichicaste de raton 162 
chancapiedras 147 
chibombo 48 
chicasquil 8 1 
chilillo 143 
chimbra 162 
Chinese laurel 65 
Chinese tallow tree 152 
chorrera 82 
Cicca antillana 1 36 
Cicca disticha 142 
cintillo 83 

Clavija septentrionalis 138 
Cleidion 79 

Cleidion denticulatum 59 
Cleidion nicaragunense 56 
Cleidion castaneifolium 25, 80 



166 



FIELDIANA: BOTANY 



Cleidion oblongifolium 80 
Cnidoscolus 80 

Cnidoscolus aconitifolius 15, 81 
Cnidoscolus adenophilus 82 
Cnidoscolus cordifolius 8 1 
Cnidoscolus tubulosus 8 1 
Cnidoscolus urens 15, 82 

ssp. adenophilus 82 
Codiaeum 82 

Codiaeum variegatum 45, 82 
cola de gato 5 1 
cola de zorro 5 1 
Conceveiba 83 
Conceveiba cor datum 65 
Conceveiba pleiostemona 33, 83 
copa del rey 1 32 
copal-che 95 
copalchf95, 101 
copper leaf 49 
coral plant 131 
coquillo 130 
Coquito 130 
costilla de caballo 5 1 
costilla de danto 5 1 
Cremophyllum spathulata 109 
Croton 84 
croton, garden 83 
Croton argenteus 29, 88 
Croton axillaris 88 
Croton benthamianus 93 
Croton billbergianus 32, 89 

ssp. pyramidalis 89 
Croton brevipes 25, 89 
Croton castaneifolium 70 
Croton costaricensis 95 
Croton decalobus 29, 90 
Croton draco 31, 90 

ssp. panamensis 90 
Croton eluterioides 95 
Croton escathos 96 
Croton glabellus 98 
Croton gland ulosus 9 1 

ssp. hirtus 9 1 
Croton grosseri 89 
Croton guatemalensis 95 
Croton hirtus 23, 91 
Croton hoffmannii 32, 91 

var. incana 91 

var. viridis 9 1 
Croton jimenezii 32, 92 
Croton jutiapensis 29, 93 
Croton killipianus 99 
Croton lanjouwensis 30, 93 
Croton lobatus 15, 93 

var. seemannii 93 
Croton macrodontus 90 
Croton matourensis 93 

var. benthamianus 93 
Croton mexicanus 29, 94 
Croton moluccanum 64 
Croton monteverdensis 95 
Croton morifolius 100 
Croton nitens 98 
Croton niveus 30, 95 
Croton oerstedianus 94 
Croton ortholobus 29, 95 



Croton ovalifolius 23, 96 
Croton pachypodus 30, 96 
Croton palanostigma 96 
Croton panamensis 90 
Croton perobtusus 98 
Croton pittieri 90 
Croton pseudoxalapensis 101 

var. cobanensis 101 
Croton punctatus 30, 97 
Croton pungens 31, 97 
Croton pyramidalis 89 
Croton reflexifolius 95 
Croton rhamnifolius 

var. caudatus 100 
Croton schiedeanus 30, 98 
Croton skutchii 98 
Croton smithianus 31, 99 
Croton sp. A 103 
Croton sp. aff. C. yucatanensis 29, 

102 
Croton speciosus 99 

ssp. tacarcunensis 99 
Croton sphaerocarpus 29, 100 
Croton standleyi 97 
Croton steyermarkianus 90 
Croton tabascensis 103 
Croton tenuicaudatus 32, 100 
Croton tonduzii 30, 101 
Croton tragioides 101 
Croton trinitatis 23, 101 
Croton triumfettoides 90 
Croton variegatus 82 
Croton watsonii 102 
Croton xalapensis 31, 101 
Croton yucatanensis 29, 102 
Cyclostigma denticulatum 90 
Cyclostigma panamensis 90 

Dalechampia 103 
Dalechampia arenalensis 105 
Dalechampia canescens 1 06 

ssp. friedrichsthallii 106 
Dalechampia cissifolia 17, 106 

ssp. panamensis 106 
Dalechampia discoreifolia 18, 107 
Dalechampia friedrichsthalii 1 06 
Dalechampia guatemalensis 107 
Dalechampia heteromorpha 18, 107 
Dalechampia molliuscula 107 
Dalechampia osana 17, 108 
Dalechampia panamensis 1 06 
Dalechampia roezliana 109 
Dalechampia scandens 17, 108 
Dalechampia shankii 17, 109 
Dalechampia spathulata 26, 109 
Dalechampia tiliifolia 17, 109 
Dalechampia trifolia 

var. cissiflora 106 
Dalechampia websteri 17, 110 
Ditaxis guatemalensis 66 
domatia 57, 58, 59, 63 
Drypetes 110 
Drypetes brownii 40, 1 1 1 
Drypetes lateriflora 40, 112 
Drypetes sp. aff. D. alba 1 1 2 
Drypetes standleyi 40, 112 



Dysopsis 1 1 3 

Dysopsis glechomoides 23, 113 

espino de play a 59 
Euphorbia (73), 113 

subgenus Chamaesyce 72, 114 
Euphorbia adinophylla 1 2 1 
Euphorbia ammannioides 74 
Euphorbia amphilmalaca 122 
Euphorbia astroites 1 1 9 
Euphorbia bahiensis 73 
Euphorbia bombensis 74 
Euphorbia brasiliensis 75 
Euphorbia buxifolia 11 
Euphorbia chiapensis 1 2 1 
Euphorbia colletioides 43, 116 
Euphorbia co tinifolia 43, 116 
Euphorbia cyathophora 1 1 6 
Euphorbia densiflora 74 
Euphorbia dioeca 75 
Euphorbia dwyeri 1 1 7 
Euphorbia elata 1 1 7 
Euphorbia enalla 1 22 
Euphorbia erithrophylla 1 20 
Euphorbia flexuosus 11 
Euphorbia friedrichsthalii 1 2 1 
Euphorbia geniculata 1 1 8 
Euphorbia globulifera 75 
Euphorbia glomifera 76 
Euphorbia graminea 42, 117 

var. subsinuata 1 1 7 
Euphorbia heterophylla 42, 1 18 

var. cyathophora 1 1 6 
Euphorbia hirta 75 
Euphorbia hoffmanniana 43, 1 1 8 
Euphorbia hypericifolia 76, 77 
Euphorbia hyssopifolia 76 
Euphorbia lasiocarpa 11 
Euphorbia leucocephala 43, 119 
Euphorbia litoralis 11 
Euphorbia mesembryanthemifolia 

11 
Euphorbia millii 

var. splendens 121 
Euphorbia morisoniana 1 1 8 
Euphorbia neriifolia 1 1 9 
Euphorbia nutans 11 
Euphorbia ocymoidea 19, 119 
Euphorbia oerstediana 42, 120 
Euphorbia opthalmica 78 
Euphorbia peplus 1 20 
Euphorbia picta 1 1 7 
Euphorbia procumbens 78 
Euphorbia prostrata 78 
Euphorbia pulcherrima 1 20 
Euphorbia schlechtendalii 43, 121 
Euphorbia segoviensis 42, 121 
Euphorbia serpens 79 
Euphorbia splendens 1 2 1 
Euphorbia thymifolia 79 
Euphorbia tirucalli 122 
Euphorbia tithymaloides 1 39 
Euphorbia valerii 1 1 7 
Euphorbia xalapensis 42, 122 
Euphorbiastrum hoffmannianum 
118 



BURGER & HUFT: FLORA COSTARICENSIS 



167 



Excoecaria caribea 57 
Excoecaria riparia 57 

flor de pascua 121 
fosforo 6 1 
frailecillo 130 
friloes saltarines 157 

gallina 143 
Garcia 122 

Garcia nutans 34, 123 
garden croton 83 
Gitara panamensis 57 
golondrina 72, 75, 79 
grosea 142 
grosella 142 
Gymnanthes 123 
Gymnanthes lucida 39, 124 
Gymnanthes guatemalensis 1 24 
Gymnanthes riparia 25, 39, 124 

harillo 127 

Hebecocca panamensis 137 

Hevea 125 

Hevea brasiliensis 125 

hierba santa 82 

Hieronyma see Hyeronima 127 

higuera 133 

higurillo 150 

Hippomane 125 

Hippomane glandulosa 153 

Hippomane mancinella 45, 125 

horla 116 

Hura 126 

Hura crepitans 45, 126 

Hura polyandra 126 

Hydrocotyle glechomoides 113 

Hyeronima 127 

Hyeronima alchorneoides 41 , 127 

var. stipulosa 128 
Hyeronima guatemalensis 128 
Hyeronima laxiflora 127 
Hyeronima oblonga 41 , 128 

var. benthamii 128 
Hyeronima poasana 1 28 
Hyeronima tectissima 1 27 
Hyperbaena leptobryosa 144 

Jacob's coat 49 
Jatropha 129 
Jatropha aconitifolia 8 1 
Jatropha adenophila 82 
Jatropha aesculifolia 1 34 
Jatropha costaricensis 16, 129 
Jatropha curcas 16, 1 30 
Jatropha cordifolia 8 1 
Jatropha dulcis 135 
Jatropha gossypifolia 16, 1 30 
Jatropha hastata 1 3 1 
Jatropha integerrima 16, 131 
Jatropha multifida 1 3 1 
Jatropha podagrica 1 3 1 
Jatropha manihot 135 
Jatropha tubulosus 8 1 
var. quinqueloba 8 1 
Jatropha urens 82 



Julocroton 84 
Julocroton argenteus 88 

keys to genera 2, 7 
kurinwacito 133 

laurel 83 

lechilla 119 

Leptopus segoviensis 1 2 1 

Mabea 132 

Mabea excelsa 39, 132 
Mabea montana 133 
Mabea occidentalis 44, 1 33 
mala 109 
manchineel 126 
mandioca 136 
manioc 136 
Manihot 133 

Manihot aesculifolia 14, 1 34 
Manihot brachyloba 14, 135 
Manihot carthaginensis 135 
Manihot dulcis 135 
Manihot esculenta 14, 135 
Manihot glaziovii 1 36 
Manihot gualanensis 1 34 
Manihot ultissima 135 
manto de Jesus 49 
manzanillo de playa 1 26 
manzanita de playa 1 26 
Margaritaria 136 
Margaritaria nobilis 38, 136 
medicine 76, 147, 150 
Moeroris stipulata 146 

nanciton 128 

Omphalea 137 
Omphalea diandra 44, 137 

var. panamensis 137 
Omphalea panamensis 137 
Ophellanthus spinosa 138 
ortiga 82 

Oxydectes costaricensis 95 
Oxydectes turrialva 9 1 

pasquite 1 1 9 
pastor 49, 121 
Pausandra 138 
Pausandra extorris 138 
Pausandra trianae 26, 138 
Pedilanthus 139 
Pedilanthus tithymaloides 139 
Pera 13 

Pera arborea 39, 140 
Pera barbellata 139 
Phyllanthus 140 
Phyllanthus acidus 142 
Phyllanthus acuminatus 22, 142 
Phyllanthus amarus 21, 143 
Phyllanthus anisolobus 144, 145 
Phyllanthus antillanus 1 36 
Phyllanthus brasiliensis 142 
Phyllanthus caroliniensis 21, 143 
Phyllanthus compressus 21, 144 
Phyllanthus conami 142 



Phyllanthus distichus 142 
Phyllanthus fluitans 140 
Phyllanthus hyssopifolium 21, 144 
Phyllanthus lathyroides 145 
Phyllanthus leptobryosa 144 
Phyllanthus mcvaughii 145 
Phyllanthus micrandrus 145 
Phyllanthus mocinianus 22, 144 
Phyllanthus niruri 21, 145 
Phyllanthus nivosus 69 
Phyllanthus nobilis 1 36 
var. hypomalaeus 136 
Phyllanthus pittieri 144 
Phyllanthus salviifolius 145 
Phyllanthus skutchii 38, 146 
Phyllanthus stipulatus 21, 146 
Phyllanthus tremulus 67 
Phyllanthus urinaria 21, 146 
Phyllanthus valerii 22, 147 
pica-pica 162 
pie de nino 139 
pie de santo 139 
pilon 128 
Plukenetia 147 
Plukenetia angustifolia 1 48 
Plukenetia penninervia 44, 148 
Plukenetia volubilis 18, 148 
poinsettia 121 

Poinsettia (subgenus) 117, 118 
Poinsettia cyathophora 1 1 6 
Poinsettia heterophylla 1 1 8 
Poinsettia oerstedianum 120 
Poinsettia pulcherrima 1 20 
Poinsettia xalapensis 122 
pringamoza 82 
purging nut 132 

quisarrd copalch 161 

rabo de goto 5 1 
red-hot cattail 5 1 
Richeria 149 
Richeria dressleri 1 49 
Richeria grandis 

var. obovata 149 
Richeria obovata 41, 149 
Ricinella triloba 58 
Ricinocarpus costaricensis 50 
Ricinocarpus irazuensis 54 
Ricinus 149 

Ricinus communis 14, 1 50 
rubber 125, 152 
ruibarbo 132 

Sagotia 150 

Sagotia racemosa 33, 151 

Sapium 151 

Sapium allenii 35, 1 52 

Sapium anadenum 1 54 

Sapium aucuparium 153 

Sapium biglandulosum 1 53 

var. oligoneurum 153 

var. sulciferum 153 
Sapium glandulosum 35, 36, 153 
Sapium jamaicense 154 
Sapium laurifolium 153 



168 



FIELDIANA: BOTANY 



Sapium macrocarpum 36, 154 
Sapium mexicanum 154 
Sapium oligoneurum 153 
Sapium pachystachys 35, 154 
Sapium pittieri 153 
Sapium pleiostachys 1 54 
Sapium rigidifolium 36, 155 
Sapium schippii 153 
Sapium sebiferum 152 
Sapium stylare 155 
Sapium sulciferum 153 
Sapium thelocarpum 1 54 
Sapium zelayensis 157 
Schaefferia lateriflora 112 
Sebastiania 155 
Sebastiana corniculata 24, 156 
Sebastiana panamensis 1 56 
Sebastiana pavoniana 38, 157 
snowbush 69 

Stilaginella benthamii 128 
Stilaginella laxiflora 127 
Stilaginella oblonga 128 



Stillingia 157 
Stillingia laurifolia 153 
Stillingia microsperma 157 
Stillingia zelayensis 36, 157 
stinging hairs 80, 82, 106, 109, 1 10, 

161, 162 
Synadenium grantii 158 

tampate 130 
tapioca 136 
tempate 130 
Tetrorchidium 158 
Tetrorchidium brevifoliura 1 60 
Tetrorchidium costaricense 34, 158 
Tetrorchidium euryphyllum 33, 34, 

159 

Tetrorchidium microphyllum 160 
Tetrorchidium molinae 160 
Tetrorchidium rotundatum 34, 160 
toxic latex 114, 126 
Tragia 161 
Tragia bailloniana 15, 18, 161 



Tragia cordata 161 
Tragia corniculata 156 
Tragia correae 18, 162 
Tragia grandifolia 59 
Tragia shankii 109 
Tragia volubilis 18, 162 
targua 92, 102 
targua bianco 102 
terre 102 
Triadica sebifera 152 

Veconcibea pleiostemona 83 

yos 152, 153 
yuca 136 
yuca amarga 136 
yuca de monte 135 

zapatero 128 
zapatilla 139 
Zuckertia cordata 161 



BURGER & HUFT: FLORA COSTARICENSIS 



169 









.. 






41 
47 









Pinat e 

AJismat. 
Butom a 



Palmae 

Bromcii 
Ponu 

Haemodonn 

Zinf 

1 

: 



C'henopi 
Portula. 






88 

100 

. 

104 
106 
108 

110 
111 

113 



. 
incl. Hum 

Simarub 

Malp^ 




















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184 























UNIVERSITY OF ILLINOIS-URBAN*