Yam Family

Roger Spencer

Herbaceous or woody climbers with twining stems and rhizomatous or tuberous roots, occasionally with aerial tubers. Leaves alternate, sometimes opposite, entire, heart-shaped to palmately lobed with 3-9 veins arching up from the base. Flower clusters forming spikes, racemes or panicles. Flowers either bisexual, or unisexual (the sexes on separate plants) small, green. Perianth segments 6 in 2 whorls, usually united at the base. Male flowers with 6 stamens in 2 whorls (1 whorl sometimes of staminodes or absent). Female flowers with ovaries inferior, of 3 united carpels with axile placentation and 2 ovules per chamber. Fruit a capsule (often 3-winged), rarely a berry.

Occasionally found in public gardens for the attractive sometimes colourful foliage, or in the tropics for the yams. Tamus communis is a summer-flowering climber from Europe, Africa and Asia that is occasionally grown for its shiny leaves and bright red (poisonous) berries each about 1 cm wide; the greenish flowers are about 4 mm wide.

Twining unisexual plants with woody or tuberous rootstock, leaves with mostly 3-9 arching veins from leaf base.

6 genera and 880 species from tropical and warm temperate regions, a few temperate. Australia has 1 genus and 5 species.

Source: Spencer, R. (2005). Dioscoreaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Lilianae
order      Dioscoreales
Higher taxa
Subordinate taxa
genus        Dioscorea L.