Dioscorea alata L.

Linnaeus, C. von (1753) Species Plantarum 2: 1033. Type: Habitat in Indiis.

Greater Yam

A vigorous multistemmed vine but stem diameters not exceeding 2 cm. Aerial tubers.

Leaf blades about 5-25 x 4.5-15 cm, petioles about 3-18 cm long, longitudinally ribbed. Usually 5-9 veins, including the midrib, radiating from the base of the leaf blade. Younger twigs usually have 4 wavy longitudinal wings. Wings resembling stipules, usually present at the base of the petiole and decurrent (running down the twigs). A single wing on each of the major veins on the underside of the leaf blade.

Male flowers: spikes 1 or 2 per axil, 1-3 cm long; sepals and petals ovate; 1.5-2 cm long, yellow; stamens 6. Female flowers: racemes 1 or 2 per axil, 10-60 cm long; perianth similar to male; staminodes absent.

Capsules broadly ovate in lateral view, retuse, 17-20 mm long; lobes to 15 mm wide.

Features not available.

An introduced species originally from SE Asia and Malesia, now naturalised in NT, CYP and NEQ. Altitudinal range from near sea level to 100 m. Grows in disturbed areas in lowland rain forest. Also naturalised on some of the Pacific Islands.

This species produces both small aerial yams or bulbils and large subterranean yams, often quite contorted.

Some of this profile information and associated coding has been adapted from Telford (1986).