Dioecious; spikelets flattened, 4–19-fld, the pistillate ones disarticulating above the glumes and between the lemmas; glumes unequal, obscurely veined, shorter than the lemmas; lemmas firm or coriaceous, smooth, obscurely many-veined, closely overlapping; low colonial perennial grasses from creeping scaly rhizomes with stiff, erect stems, numerous narrow, usually involute blades with overlapping sheaths, and small panicles of large, crowded spikelets. 4, New World.