Glabrous trees, shrubs or, for the greater part, vines. Leaves decussate, simple, entire, penninerved, exstipulate, mostly provided with fine, pellucid lines (spicular cells) parallel to the secondary nerves and then bearded on fracture. Spikes ramified or simple, axillary or often cauline, dioecious, each one with 2 opposite basal scales and several collars containing moniliform hairs and sessile flowers, either numerous spirally arranged male ones below a ring of some sterile female ones, or a ring of few fertile female ones. ♂ Flower: a claw-shaped, transversely splitting perianth and a central stamen with 2 (in G. gnemonoides one) apical, yellow microsporangia that open by an apical median split. ♀ Flower: a fleshy outer envelop (‘perianth’) and 2 thin inner ones (‘integuments’), the innermost with a long, slender, apical tube, and an orthotropous ovule; sterile ♀ flower without the middle envelop. Fruit pink (in G. neglectum and G. oxycarpum yellow), consisting of the fleshy outer envelop, which in some spp. is narrowed into a stalk, the hardened, ribbed middle envelop, the thin, silky, inner envelop, and a large, horny seed with small embryo. Distr. About 30 species, of which 7 in northern S. America, 2 in western tropical Africa, the remainder in tropical Asia from Bombay to Fu-Kien, through Malaysia to Fiji, neither in Formosa nor in Australia or New Caledonia. Centre of present development: eastern Malaysia. The distributional areas of several species present some marked lines within the archipelago.