III. Subfam. Podostemoideae (Warming) Engler (1928).
Young flowers enclosed in spathella (a membranous, non-vascularised cover); tepals 2--20, rarely lacking, not imbricate, linear, spatulate or subulate; stamens 1--40, often free; many genera with Y-shaped androecium, consisting of 2 stamens borne on an andropodium (a common stalk); pollen tricolpate or sometimes tetracolpate or pentacolpate, shed in monads or dyads (Diamantina in tetrads); ovary 2-locular or rarely due to absence of a septum 1-locular; capsule opening by 2 equal or unequal valves, or rarely indehiscent. 45 genera, tropical America to temperate eastern N America, tropical and subtropical Africa, Madagascar, tropical S and SE Asia to temperate E Asia and tropical Australia.