Flora of Barro Colorado Island

Dioscorea polygonoides

H. & B. ex Willd., Sp. Pl. 4:795.1806

Dioecious twining vine; stems, petioles, and inflores­cences weakly ribbed, the ribs minutely scabrid; stems twisting to the left. Leaves alternate; petioles 1.5-6 cm long; blades ovate-orbicular to ovate, narrowly acumi­nate, sometimes falcate, deeply to broadly cordate at base, mostly 4-11 cm long, 2.5-8.5 cm broad, obscurely pellucid-lineolate, eglandular; veins (9)11, palmate, the cauline veins 3, the veins of lower surface often minutely scabrid (especially after drying); juvenile plants often with a single     ovate-cordate leaf arising from an under­ground stem, the petiole to 1.3 cm long, the blade often mottled with gray; leaves of the juvenile climbing stems larger than on adults, to 22 cm long and 13.5 cm wide, the petiole to 8 cm long. Inflorescences axillary; rachises minutely scabrid; flowers to 2 mm broad; staminate spikes 2-4 in leaf axils,10-30 cm long, usually unbranched, sparsley flowered; flowers greenish, sessile, in few-­flowered fascicles, the perianth segments ovate, 1-1.3 mm long, united in lower half, each with a ± prominent medial vein; stamens 3, inserted on perianth; anthers extrorse, separated by a broad connective; staminodia 3, bifid at apex, about as long as stamens; ovary rudiment conspicuous. Pistillate spikes solitary or paired, un­branched, less than 15 cm long, the flowers sessile; sta­mens lacking; ovary ca 3 mm long; styles 3, minute, con­ical; stigmas bifid. Capsules 3-winged, obovate to oval, 2.5-3 cm long, to ca 2 cm wide, glabrous; seeds winged all around. Croat 12877, Shattuck 582.

Occasional, in the forest and at the margins of clearings; probably about as abundant as D. urophylla with which it is confused. Seasonal behavior uncertain. Apparently flowers in the early dry season (December to February); the fruiting season is not known.

Standley cited Shattuck 582, which is this species, as D. macrostachya. Morton in the Flora of Panama (1945) reported that the species lacks pellucid lineations. Though they are not as prominent as in           D. urophylla, pellucid lineations are usually present, at least after the specimens are dried.

Mexico to Peru and Brazil; West Indies. In Panama, known only from tropical moist forest in the Canal Zone and in adjacent Panama.

Photos from STRI Digital Archive

  • Dioscorea polygonoides Inflorescence
  • Dioscorea polygonoides flower plant
  • Dioscorea polygonoides leaf
  • Dioscorea polygonoides leaf
  • Dioscorea polygonoides
  • Dioscorea polygonoides