Flora of Barro Colorado Island

Dioscorea urophylla

Hemsl., Biol. Centr.-Amer. Bot. 3:361.1884

Bejuco de saina

Dioecious twining vine, glabrous; stems usually twisting to the left, with short broad-based spines at the base of larger leaves. Leaves alternate to opposite; petioles 3.5-9.5 cm long (to 14 cm long on juvenile plants); blades ovate, narrowly long-acuminate, truncate to weakly cordate at base, 5-14 cm long, 3-8.5 (14) cm wide, thin, conspicu­ously pellucid-lineolate and glandular-dotted on lower surface (glands sparse to lacking on upper surface); veins 7-9, palmate. Staminate spikes 1-3 per axil, to ca 50 cm long (usually less than 10 cm), unbranched or branched (especially when long); flowers greenish-yellow, solitary, sessile; tepals oblong, 2-3 mm long, acute at apex, con­nate at base, spreading at anthesis; stamens 6 (in 2 whorls of 3 each), ca 1.3 mm long, inserted on and held at about same level as tepals; anthers introrse; pollen golden, tacky; pistillode much shorter than filaments, trilobate. Pistillate spikes 1 per axi1,10-20 cm long; flowers sessile; tepals 6, 2-3 mm long; stamens 6 (probably nonfunctional but with some pollen), adnate to lower part of tepal, ca 0.7 mm long; ovary glabrous, ca 3.5 mm long; style single, 1.3-2 mm long, conical; stigmas bilobed, flattened. Cap­sules    3-winged, oblong-elliptic, acute or apiculate at apex, ± rounded below, 2.3-3 cm long, 1.3-1.6 cm wide,         3-valved, the valves coriaceous, tuberculate (especially medially); seeds samaroid, 2-2.5 cm long (including wing), 6-8 mm wide, brown. Croat 6704, Foster 1177.

Occasional, in the forest. Flowers principally in the rainy season (June to September, occasionally as early as April). The fruits mature during the following dry season (December to April).

Capsules of this species are almost identical to those of D. cymosula Hemsl., which can be distinguished by having the persisting flower and pedicel densely pilose, whereas D. urophylla is wholly glabrous. The species is most easily confused with D. polygonoides and D. macro­stachya.

Panama and Peru; probably in intervening regions as well. In Panama, known from drier regions of tropical moist forest in the Canal Zone (both slopes) and Herrera, Panamd, and Darién; known also from premontane moist forest in the Canal Zone and Panama and from premon­tane wet forest in Colon (Santa Rita Ridge).

See Fig. 143.

Photos from STRI Digital Archive

  • Dioscorea urophylla Inflorescence
  • Dioscorea urophylla Inflorescence
  • Dioscorea urophylla flower plant
  • Dioscorea urophylla leaf
  • Dioscorea urophylla plant
  • Dioscorea urophylla plant
  • Dioscorea urophylla