Aloes and Lilies of Ethiopia and Eritrea

Distribution and
classification
DIOSCOREACEAE
ASPARAGUS 305
The family includes twining or climbing, seldom erect,
herbs arising from tubers most often derived from starchy
rhizomes. The leaves are alternate or opposite, often
ovate-cordate, but sometimes with 3–7 digitate leaflets.
The inflorescences are spikes, racemes or panicles. The
flowers are usually unisexual (very rarely bisexual).
There are 6 perianth segments. Stamens 3 + 3, but the
inner ones sometimes reduced. The ovary is inferior,
rarely semi­inferior or superior, 3­locular, with axile
placentation. The fruit is a dehiscent capsule or berry
with winged seeds.
Dioscoreaceae is a mainly tropical family, including about
7 genera, with the greatest diversity in central and south
America, Indo­Malaysia, Micronesia and Madagascar.
Representatives occur also in Europe and Africa, but the
diversity here is lower. Only one genus, Dioscorea, is
represented in tropical Africa.
DIOSCOREA L.
The genus includes twining or climbing herbs, often
prickly below where browsers have access, but
sometimes unarmed. The flowers are unisexual and the
plants unisexual (dioecious). The male inflorescences are
spicate, racemose or rarely cymose, axillary or forming
panicles at the ends of leafless branches; male flowers
with campanulate to spreading tepals, and with six
stamens, either all fertile or 3 reduced to stami nodes. The
female inflorescences are spicate and axillary; female
flowers with tepals similar to the male ones. The capsules
are triangular or deeply three­lobed dehiscing with 3
valves, and with 1–2 seeds in each locule. The seeds are
winged or rarely wingless.
The genus includes c. 600 species, occurring mainly in