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aerial yam, air potato, air yam, bitter yam, potato yam

Habit Plants tuberous or not; tubers, when present, buried just below ground surface, not stalked, globose, weighing less than 1 kg.
Stems

twining counter-clockwise, climbing to more than 20 m, often flecked with purple, unwinged or rarely narrowly winged, terete, producing axillary bulbils frequently greater than 5 cm in diam. in leaf axils.

Leaves

alternate throughout, 5–25 × 5–26 cm;

petiole usually somewhat shorter than blade, base clasping, basal lobes stipulelike, 1–4 mm wide;

blade 5–11-veined, broadly ovate-cordate, glabrous, base orbicular, margins entire, apex long-acuminate.

Pistillate flowers

perianth greenish white, not changing color;

tepals as in staminate flowers;

staminodes 6, smaller than fertile stamens. Capsules not reflexed at maturity, longer than wide, 1.8–2.8 × 1–1.5 cm.

Seeds

unilaterally winged, 12–20 mm.

Staminate

inflorescences axillary, borne singly, spicate or paniculate, cymose, to 70 cm;

cymes reduced to 1 sessile bracteolate flower, internodes ca. 2 mm;

secondary axes to 6 per node, fasciculate, subtended by deltate bracteoles or sometimes leafy bracts, 3–20 cm.

Pistillate

inflorescences borne singly or fasciculate, to 6 per axil, spicate;

spikes bearing to 50 flowers, 6–40 cm, subopposite to 8 mm apart. Staminate flowers fragrant;

perianth white, becoming purple;

tepals in 2 similar whorls, spreading at anthesis, lanceolate, (1–)2–5 mm;

fertile stamens 6 in 2 equal whorls;

anthers as long as or longer than filaments; thecae distinct, not spreading.

2n

= 80, 100.

Dioscorea bulbifera

Phenology Flowering late summer–early fall.
Habitat Near ponds, marshes, drainage canals, disturbed woods and thickets, waste areas
Elevation 0 m (0 ft)
Distribution
from FNA
FL; tropical Asia; tropical Africa [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Dioscorea bulbifera is the most widely distributed of all Dioscorea species. It is found throughout the tropics and is thought to be native to both Africa and Asia. The tubers are either small and bitter or do not form at all. The bulbils are eaten, although this species is not widely consumed outside of Oceania. It is weedy in Florida and probably elsewhere in the Gulf States, but I have not seen any specimens to document its range outside Florida. Plants in the flora area rarely flower, and those that do are usually pistillate; I observed no staminate flowers.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 26, p. 484.
Parent taxa Dioscoreaceae > Dioscorea
Sibling taxa
D. alata, D. floridana, D. polystachya, D. sansibarensis, D. villosa
Name authority Linnaeus: Sp. Pl. 2: 1033. (1753)
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