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Draft Treatments
ARECACEAE
By M. H. Grayum
English, final draft: placed 1/Apr./2000
Terrestrial plants (sometimes paludal), acaulescent or stems
rhizomatous to (usually) erect, often massive and arborescent,
solitary or cespitose (but the aerial portion unbranched in ours),
occasionally (Desmoncus) scandent, smooth to spiny. Petioles
unarmed or spiny, with or without a distal hastula (ligule-like
structure). Lvs. simple or bifid to pinnately compound or palmately
divided, spiraled or (rarely) di- or tristichous, ± clustered at
apex of stem, ± strongly plicate, glabrous to pubescent and/or
spiny, rarely (Attalea, Reinhardtia) fenestrate, the
margins entire to serrate. Plants hermaphroditic, monoecious, or
(Chamaedorea) dioecious, the infls. axillary (rarely
apparently terminal), interfoliar (borne among the lvs.) or
infrafoliar (borne below the lvs.), subtended by a usually 2-keeled
prophyll. Infl. spicate to racemosely or paniculately branched.
Peduncle obsolete to elongate, bearing 0--many, often conspicuous
bracts. Fls. usually sessile and much reduced, bisexual or unisexual
(in which case often borne in triads of 2 male fls. and 1
female fl.), ± actinomorphic, usually bracteate. Perianth
usually clearly differentiated into calyx and corolla, of usually 3
distinct or ± connate sepals and petals (respectively). Stamens
3 or 6--indefinite, distinct or ± connate; staminodia usually
evident in female fls., sometimes connate. Pistils 1 (--4); if 1,
monomerous (or pseudomonomerous) to compound; ovary superior, with 1
or 3 (+) locules; styles 1--3 (+), or not evident; stigmas erect or
recurved; ovules 1 per locule; placentation axile, basal, or
subapical. Frt. a usually 1-seeded drupe, glabrous to spiny or scaly,
sometimes (Iriartea, Socratea) ± dehiscent. Seeds
with copious endosperm. Ca. 200 genera and perhaps 2500 spp.;
pantropical, with very few spp. in temperate regions; many spp. are
cultivated for ornament, and some for food.
Palms are most abundant and diverse in Costa Rica in humid,
lowland forests. They are usually easily recognized by their
familiar, plicate lf.-blades. The only other family in Costa Rica
with which Arecaceae can easily be confused is Cyclanthaceae, which
have many-seeded berries rather than single-seeded drupes. See under
the last-mentioned family for further information.
Numerous exotic palms are cult. for ornamental purposes in Costa
Rica. Probably the most frequent of these is the Madagascan Dypsis
lutescens (H. Wendl.) Beentje & J. Dransf.
(Chrysalidocarpus lutescens H. Wendl.) [Poveda 680
(CR)], commonly called areca. This is a smallish (to ca. 7 m),
cespitose species with yellowish petioles and lf.-rachises and a
glaucescent crown-shaft.
Henderson, A., G. Galeano & R. Bernal. 1995. Field guide to
the palms of the Americas. Princeton Univ. Press, Princeton, NJ.
Uhl, N. W. & J. Dransfield. 1987. Genera palmarum. L.
H. Bailey Hortorium & International Palm Soc., Lawrence, KS.
1 Lf.-blades palmately divided and veined, ± suborbicular in
outline, the midrib obsolete or very short; plants hermaphroditic,
the fls. bisexual
2 Stems cespitose; petioles armed marginally with sharp,
triangular spines; rare, N Atl. slope...Acoelorraphe
2' Stems solitary; petioles unarmed (sometimes sharp-edged, but
lacking spines)
3 Stems ± densely armed with usually branching root-spines,
especially toward base; lf.-blades split centrally nearly or quite to
the base; ripe frts. white; widespread...Cryosophila
3' Stems unarmed; lf.-blades with central split not or scarcely
deeper than lateral splits; ripe frts. blackish; rare and local
4 Stem apex densely covered with matted, reddish brown
petiole-sheath fibers; midrib of lf.-blades obsolete (ca. 6--8 cm);
pistils 3 at anthesis (the styles connate); ripe frts. ca. 1.3--2.2 X
1.4--2.2 cm, with apical stigmatic residue; ca. 700--1000 m, Atl.
slope Cords. Guanacaste and Talamanca, Pac. slope Fila Costeña...Colpothrinax
4' Stem apex mostly bare, the petiole sheaths sparingly fibrous
marginally; midrib of lf.-blades elongate (ca. 90--125 cm); pistil 1;
ripe frts. ca. 0.9--1.1 X 0.9--1.1 cm, with basal stigmatic residue;
ca. 0--200+ m, Talamanca coast, lower Río Tulín (R.
Tusubres) basin...Sabal
1' Lf.-blades simple and bifid to pinnately compound, pinnately
veined, ± elongate in outline; plants monoecious or dioecious,
the fls. unisexual
5 Stems solitary, to 20--30 m tall, supported at base by dense or
open cone of spiny stilt-roots to 1--2+ m tall; petiole sheaths
closed, forming a distinct, greenish crownshaft; lflts. large,
wedge-shaped, cuneate at base, praemorse distally, splitting
longitudinally into narrow segments arranged in various planes;
stamens 10--65; frts. ± dehiscent, the seeds ultimately falling
free
6 Stilt-roots to ca. 100, blackish, forming a very dense cone;
terminal lflt. entire; infls. decurved in bud; stamens ca. 10--17;
frts. (and seeds) ± globose...Iriartea
6' Stilt-roots to ca. 25, brown, forming an open cone; terminal
lflt. bifid; infls. erect in bud; stamens ca. 30--65; frts. (and
seeds) ovoid-cylindric...Socratea
5' Stems various, but never supported by spiny stilt-roots;
petioles forming a crownshaft (some Chamaedorea spp.,
Euterpe, Hyospathe, Prestoea, Oenocarpus)
or not; lflts. wedge-shaped (Aiphanes, Reinhardtia) or
not, arranged in a single or various planes; stamens 3--6 (--28,
Reinhardtia; --45, Welfia); frts. indehiscent, the
seeds not falling free
7 Plants at least sparingly armed with spines on stem, petioles,
lf.-rachis, and/or lf.-blades
8 Plants scandent; lf.-blades pinnately compound, with rachis
prolonged distally into a long appendage (cirrus) bearing
rigid, retrorse acanthophylls (modified lflts.)...Desmoncus
8' Plants erect; lf.-blades simple or pinnately compound, then
with rachis not prolonged distally, or prolonged in a filamentous
extension lacking acanthophylls
9 Lvs. pinnately compound, the lflts. cirrhous at apex; infl.
spicate; rare, Pen. Osa...Desmoncus
9' Lf.-blades simple or pinnately compound, then lflts. acute to
acuminate or caudate at apex; infl. branched
10 Stems and petioles without spines, the lf.-rachis ±
inconspicuously spiny along the adaxial keel; lf.-blades with spines
restricted to main veins (on adaxial side) and margins of lflts.;
lf.-blades ca. 5--10+ m long, pinnately compound, the lflts. very
numerous (ca. 95--205 per side) and arranged in various planes;
infls. paniculately branched; frts. covered in 9--11 vertical rows of
closely overlapping, glossy scales; locally abundant in lowland
swamps...Raphia
10' Stems, petioles, or lf.-rachis spiny conspicuously; lf.-blades
spiny or not; lf-blades to ca. 5 m long, simple or pinnately
compound, the lflts. various; infls. racemosely branched; frt. smooth
to spinulose, but not scaly; various habitats
11 Stems stout, solitary; spines short and stout, restricted to
petiole margins, the plants otherwise unarmed; infls. unisexual,
massive and condensed, the rachillae with spinelike tips...Elaeis
11' Stems various; spines slender, terete or flattened, ±
uniformly distributed on petiole (not restricted to petiolar margins)
and usually present elsewhere (stem, lf.-rachis, and/or lf.-blades);
infls. bisexual, condensed to open, the rachillae [not prominently
spinelike at tips]
12 Stems solitary, stout, subarborescent to arborescent;
lf.-blades pinnately compound, ± whitish below
13 Dead lvs. persistent, skirting upper half of trunk; spines
terete or subterete (flattened adaxially); female fls. with distinct
sepals and petals; seasonally dry forests, mostly on Pac. slope...Acrocomia
13' Dead lvs. caducous, not skirting trunk; spines strongly
flattened; female fls. with sepals [and sometimes petals] connate in
a truncate to shallowly 3-lobed cup or tube; wet forests of both
slopes...Astrocaryum
12' Stems cespitose, slender or rarely (Bactris gasipaes)
stout and arborescent; lf.-blades simple to pinnately compound,
± concolorous (but see Bactris caudata, B.
grayumii)
14 Lf.-blades pinnately compound, the lflts. wedge-shaped, cuneate
at base, praemorse distally; peduncles elongate, divergent; very
rare, Fila Costeña...Aiphanes
14' Lf.-blades simple to pinnately compound, then with lflts.
linear to narrowly elliptical or oblanceolate, variously narrowed at
base, acute to caudate distally; peduncles usually relatively short,
recurved; widespread...Bactris
7' Plants unarmed, lacking spines
15 Lf.-blades simple, bifid at apex
16 Infls. spicate
17 Stems cespitose
18 Stems ca. 1--2.5 m tall; lf.-blades with primary lateral veins
ca. 17--32 per side, the margins subentire; floral triads deeply
sunken in bilabiate rachillar pits; ripe frts. ca. 0.5--0.6 X
0.5--0.55 cm, subglobose, with basal stigmatic residue; 1300--1900 m,
cent. Pac. slope...Geonoma
18' Stems ca. 0.15--1.2 m tall; lf.-blades with primary lateral
veins ca. (7--) 8--10 (--11) per side, the margins very coarsely
serrate or doubly serrate; floral triads not sunken in rachillar
pits; ripe frts. ca. 0.9--1.3 X 0.6--0.8 cm, ± broadly
ellipsoidal to obovoid, with apical stigmatic residue; 50--250 m, N
Atl. slope...Reinhardtia
17' Stems solitary
19 Stems green; foliage virtually glabrous; lf.-blades marginally
toothed (sometimes ± obscurely), at least distally; plants
dioecious; fls. essentially ebracteate, solitary or in irregular
groups, superficial or slightly immersed...Chamaedorea
19' Stems brownish; foliage usually ± scurfy or scaly,
especially petioles and main lf. veins on abaxial side; lf.-blades
marginally entire; plants monoecious; fls. borne in bracteate triads
in bilabiate pits [Proceed to couplet 35].
16' Infls. branched
20 Stems cespitose; lf.-blades with margins coarsely serrate or
doubly serrate; male fls. with ca. 14--17+ stamens; frts. with apical
stigmatic residue...Reinhardtia
20' Stems solitary or cespitose, if cespitose then lf.-blades with
margins subentire; male fls. with 3 or 6 stamens; frts. with basal
stigmatic residue
21 Stems green; foliage virtually glabrous; peduncular bracts
usually > 1; fls. essentially ebracteate, solitary or in lines,
superficial or slightly immersed
[Proceed to couplet 38].
21' Stems brownish; foliage usually ± scurfy or scaly,
especially petioles and main lf. veins on abaxial side; peduncular
bract usually 1; fls. borne in bracteate triads in bilabiate pits
22 Labia of pits immersed, the margins later recurved; ovary
3-celled at anthesis, the style apical; frts. with fibrous mesocarp...Asterogyne
22' Labia of pits elevated, later splitting medially; ovary
1-celled at anthesis, the style basal; frts. with mesocarp virtually
lacking fibers...Geonoma
15' Lf.-blades (at least some) pinnately divided to compound
23 Frts. > 10 cm diam., with thick, dry, fibrous mesocarp...Cocos
23' Frts. < 10 cm diam., with usually thin, fleshy mesocarp
24 Frts. > 3 cm diam., globose to 3-lobed, ± woody,
covered with pyramidal, wartlike projections; swamp forests near
coast...Manicaria
24' Frts. usually < 3 cm diam., globose to ovoid or ellipsoid
(never lobed), usually fleshy, smooth to (rarely) minutely echinulate
25 Petiole sheaths closed and forming a conspicuous crownshaft
usually > 0.5 m long; ± slender canopy or subcanopy trees,
the fertile stems mostly > 4 m tall; lf.-blades with numerous,
± narrow pinnae; infls. racemosely branched; ovary 1-celled
26 Stems solitary; crownshaft bright green; infl. rachillae
densely covered with whitish hairs; widespread, 0--1150 m...Euterpe
26' Stems cespitose; crownshaft usually grayish to purplish; infl.
rachillae glabrous or inconspicuously pubescent
27 Lf.-blades whitish or glaucous-looking below; infl. rachillae
pendent, closely spaced, all borne on abaxial side of short rachis,
the whole resembling a horse's tail; frts. > 1.2 cm diam.; 0--350
m, Pac. slope...Oenocarpus
27' Lf.-blades ± concolorous; infl. rachillae ±
divergent to arching, well distributed along and around the ±
elongate rachis; frts. < 1.2 cm diam.; widespread, (1000--)
1400--2450 m...Prestoea
25 Petiole sheaths open, or closed and forming a brief crownshaft
< 0.5 m long; understory subshrubs to canopy trees; lf.-blades
simple to pinnately compound; infls. spicate to racemosely or
paniculately branched; ovary 1- (rarely) or 3-celled
28 Stout, subcanopy trees, the stems solitary, 10+ cm diam. and
usually > 7 m tall; lf.-blades > 3 m long, regularly pinnate
with > 40 lflts. per side; frts. to > 1.5 cm diam.
29 Lflts. blunt and strongly inequilateral at apex; young. lvs.
green; infls. interfoliar, the rachillae > 15, shorter than
peduncle, < 1.3 cm wide; stamens 6; frts. ± ellipsoidal, >
4.5 cm long; seasonally dry forests, mainly on Pac. slope...Attalea
29' Lflts. acuminate and ± symmetrical at apex; young lvs.
reddish brown; infls. quickly becoming infrafoliar, the rachillae
< 15, longer than peduncle, > 1.3 cm wide; stamens ca. 39--45;
frts. ± dorsiventrally compressed, almond-shaped, < 4.5 cm
long; wet forests, Atl. slope and Golfo Dulce region...Welfia
28' Slender understory plants or (rarely) subcanopy trees, the
stems solitary or cespitose, to ca. 10 cm diam., to ca 6 (--10) m
tall; lf.-blades < 3 m long, regularly or irregularly pinnate with
up to 45 lflts. per side; frts. < 1.5 cm diam.
30 Stems cespitose; lflts. ± praemorse distally, sometimes
fenestrate at base, very unequal [the terminal lflt(s). somewhat to
much wider]; stamens ca. 7--28...Reinhardtia
30' Stems solitary or cespitose; lflts. acute to acuminate
distally, never fenestrate, equal or unequal; stamens (3) 6
31 Infls. spicate; stems solitary
32 Stems green; lvs. virtually glabrous; plants dioecious; fls.
essentially ebracteate, solitary or in irregular groups (not
regularly in triads)...Chamaedorea
32' Stems brownish; lvs. ± scurfy or scaly, especially on the
petiole and main lf. veins on abaxial side; plants monoecious; fls.
bracteate, mostly in triads
33 Stems > 2.5 m tall; infls. infrafoliar, the peduncle shorter
than the rachilla; ripe frts. to ca. 2.5 cm long...Pholidostachys
33' Stems obsolete to (exceptionally) ca. 2.5 m tall; infls.
interfoliar, the peduncle usually longer than the rachilla; ripe
frts. to 2.0 cm long
34 Fls. superficial or scarcely immersed in rachilla; male fls.
with sepals basally connate in a cup; fls. of both sexes with
distinct petals; female fls. lacking staminodia; frts. with apical
stigmatic residue...Neonicholsonia
34' Fls. deeply sunken in bilabiate pits; male fls. with distinct
sepals; fls. of both sexes with petals connate, at least basally;
female fls. with staminodia connate in a truncate to 6-toothed or
-lobed tube; frts. with basal stigmatic residue
35 Peduncular bract inserted distally on peduncle (just below
flowering rachilla), leaving a conspicuous annular scar; labia of
pits immersed, the margin later recurved (sometimes also splitting
medially); petals of female fls. connate for most of their length in
an apically 3-lobed tube; ovary 3-locular, the style apical; frts.
with fibrous mesocarp...Calyptrogyne
35' Peduncular bract inserted basally on peduncle, not leaving a
distal, annular scar; labia of pits elevated, later splitting
medially; petals of female fls. connate basally, free distally; ovary
1-locular, the style basal; frts. with mesocarp virtually lacking
fibers...Geonoma
31' Infls. branched; stems solitary or cespitose
36 Stems brownish; infls. racemosely to paniculately branched;
fls. deeply sunken in bilabiate pits; ovary 1-celled, the style basal...Geonoma
36' Stems brownish or green; infls. racemosely or (rarely)
subpaniculately branched (with some basal rachillae forked); fls.
superficial or scarcely immersed; ovary 1- or 3-locular, the style
central
37 Stems green; foliage virtually glabrous; peduncular bracts
usually > 1; fls. essentially ebracteate, solitary or in lines;
ovary 3-locular; frts. with basal stigmatic residue
38 Plants dioecious; fls. usually solitary, occasionally in small
fascicles; ripe frts. < 2.0 cm (usually < 1.5 cm) long,
purplish to black (or, if yellow to red, infls. unbranched)...Chamaedorea
38' Plants monoecious; fls. borne in lines (acervuli) of 1
(--2) female and 5--15 male fls.; infls. branched; ripe frts. to
1.5--2.0+ cm long, yellow to red...Synechanthus
37' Stems brownish or green; foliage ± scurfy or scaly,
especially on the petiole and main lf. veins on abaxial side; ovary
1-locular; frts. with subapical to basal stigmatic residue
39 Stems green, cespitose; male fls. (at least some) pedicellate;
female fls. with sepals connate in basal half; frts. narrowly ovoid,
with basal stigmatic residue...Hyospathe
39' Stems brownish, solitary or cespitose; male fls. sessile;
female fls with distinct sepals; frts. subglobose, with lateral
stigmatic residue...Prestoea
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