Dioecious or monoecious, lianes or climbing shrubs. Leaves alternate. Inflorescences of spikes or racemes. Flowers unisexual. Calyx 0. Petals forming a 4(-5-) lobed corolla, which is persistent in fruit. Male flowers: stamens alternating with petals; vestigial ovary present. Female flowers: vestigial staminodes alternating with petals; ovary ovoid, crowned by a sessile stigma. Fruits broadly ovoid, usually flattened; endocarp spiny on the inner face. Derivation of name: from Pyren which is Greek for fruit-stone or kernel and akanthos which is thorn. It refers to the peg-like or thorn-like protuberances that impact the inner walls of the fruit. Worldwide: 20 species in the Old World tropics. Zimbabwe: 2 taxa. |