Vines and Climbing Plants of Puerto Rico and the Virgin Islands

Vines and Climbing Plants of Puerto Rico and the Virgin Islands 427
7. Dioscorea trifida L. f., Suppl. Pl. 427.1781.
Fig. 176. J-L
Non-woody vine, twining, attainig several
meters in length. Stems glabrous or puberulent,
obtusely quadrangular, with winged projections
along the borders. Leaves alternate, palmate (5lobate),
9-11-veined, 15-21 × 15-25 cm,
membranaceous, the lobes ovate-lanceolate,
acuminate at the apex, the base cordiform; upper
surface glabrous, the veins slightly prominent;
lower surface puberulent along the prominent
veins; petioles 5-19 cm long, with 4 longitudinal
wings, swollen at the base. Inflorescences axillary;
the staminate ones paniculate; the pistillate ones
in racemes. Staminate flowers in lateral cymes,
sessile, perianth cream-colored, 1.5-6 mm long,
the stamens 6; pistillate flowers solitary,
hypanthium pubescent, the tepals ca. 2.5 mm long.
2. RAJANIA
Capsules oblong-elliptical in outline, 2.5-3.4 cm
long by 1.5 cm wide.
Phenology: Unknown.
Status: Exotic, apparently naturalized,
uncommon.
Distribution: According to Britton and Wilson
(1924) this species grows spontaneously in Puerto
Rico in areas where it was formerly cultivated; I
know collections only from the Agricultural
Experiment Station. Also throughout the Antilles
and South America.
Cultivated Species:
Dioscorea esculenta (Lam.) Burkill, D.
floribunda Mart. & Gal., D. friedrichsthalii R.
Knuth, and D. rotundata Poir. are cultivated in
Puerto Rico, but no evidence exists that they have
become naturalized or have escaped from
cultivation.
Dioecious vines, herbaceous, twining; bulbils elongate. Stems cylindrical. Leaves alternate, entire,
petiolate. Inflorescences axillary, of racemes or racemiform thyrses, pendulous or ascendant. Flowers
6-merous; the staminate ones commonly produced in lateral cymes along a racemiform thyrse; fertile
stamens 6; the pistillate ones produced in racemes; styles bifid. Fruit an indehiscent samara, with a
distal wing. An Antillean genus, of about 25 species.
1. Rajania cordata L., Sp. Pl. 1032. 1753.
Fig. 177. A-L
SYNONYM: Rajania sintenisii Uline
Guáyaro, Bejuco de guaragüao, Ñame
gulembo, White yam
Non-woody vine, climbing, twining, glabrous,
attainig 3-10 m in length. Stems slender,
cylindrical, strong, glabrous. Leaves alternate,
glabrous, 4-11.5(20) × 2-6.5(12) cm, 5-9-veined,
coriaceous or less frequently chartaceous, ovate,
lanceolate, or less frequently hastate, the apex
acute or acuminate, the base cordiform to almost
truncate; upper surface slightly shiny, with the
venation flat or slightly prominent; lower surface
with prominent venation; petioles 2-7 cm long,
cylindrical, pulvinate at the base. Inflorescences
axillary, racemose, pendulous or ascendant.
Staminate inflorescences solitary or fasciculate,
4-25 cm long, the flowers grouped in lateral
cymes, the cymes stipitate, 1-3 per node; flowers
with the perianth white or cream-colored, 0.9-1.1
mm long, the stamens 6. Pistillate inflorescences
4-30 cm long, with solitary flowers distributed
along the peduncle; flowers with the perianth 1-
1.3 mm long, the hypanthium ca. 1.5 mm long.
Fruits samaroid, (1.1)1.6-3.2 cm long, flattened,
usually reddish or burgundy, with a wing in a
lateral distal position.
Phenology: Flowering from July to March and
fruiting from September to June.
Status: Native, rather common.
Distribution: In moist forests at middle to
upper elevations, along the Cordillera Central and
in the northern limestone zone. Also on Vieques,
St. Croix, and St. Thomas; throughout the
Antilles.
Public Forests: Carite, El Yunque, Guajataca,
Guilarte, Maricao, Río Abajo, Susúa, and Toro
Negro.