Flora of the Hawaiian Islands
Monocotyledon Literature for Dioscorea bulbifera
Wagner et al., 1990, 1999; Lorence & Wagner, 2019.
   Dioscoreaceae -- The Tacca, Yam Family Bibliography
      Dioscorea bulbifera

Common name(s): yam, air potato, bitter yam, hoi, pi`oi (Kaua`i)
General Information
DistributionIn the Hawaiian Islands, a Polynesian introduction on Kaua`i, O`ahu, Moloka`i, Maui, Hawai`i.

Stems twining to the left, to 30 m long, slightly angled, glabrous, never with prickles. Tubers nearly always solitary, 5‒8 cm in diameter.
Leaves simple, alternate; petiole 6‒16 cm long, axil usually with warty brown bulbils; blade broadly ovate, 4‒24 cm long, 3‒20 cm wide, 7‒11-veined, glabrous, chartaceous, base cordate, apex shortly acuminate.
Staminate flowers in slender spikes to ca. 15 cm long, solitary or in fascicles of 2‒4 or in elongate panicles, flowers widely spaced, each subtended by 2 unequal, ovate bracts; tepals ovate-lanceolate, 1.5‒3 mm long; stamens 6, all fertile; ovary rudimentary; pistillate flowers in pendent, rather stiff, simple spikes to 35 cm long, in fascicles of 3‒6; flowers 5‒6 mm long, tepals lanceolate, 1.3‒1.6 mm, staminodes 6, ovary winged, stigmas irregularly bilobed.
Fruit ca. 25 mm long, with wings ca. 8 mm wide.
Seeds winged on basal side only.
2n = 36, 40, 54, 60, 70, 80, 98 100.
Naturalized and propagating vegetatively by means of stem tubers that fall to the ground and grow readily.