Plants perennial; dioecious. Culms 2-15 m; internodes solid. Leaves cauline; sheaths longer than the internodes, persistent, distal sheaths strongly overlapping; blades leathery, not pseudopetiolate, articulated with the sheaths, midveins conspicuous, those below midculm length disarticulating at maturity. Inflorescences terminal, panicles. Pistillate spikelets laterally compressed, with 2 florets; disarticulation above the glumes and between the florets; glumes unequal, exceeding the florets, lower glumes shorter and less firm than the upper glumes; calluses linear, glabrous; lemmas long silky-pilose distally, apices elongate, narrow, unawned; style branches 2, free; rachilla extension absent. Staminate spikelets with 2-4 florets; disarticulation below the terminal florets, glumes and lower floret(s) remaining attached; glumes subequal, membranous; lemmas membranous, glabrous or sparsely short pilose, (0)1(3)-veined; anthers 2. Caryopses oblong; hila punctate, x = 11.
Discussion
The tribe Gynerieae includes only one genus, the neotropical genus Gynerium. The position of the tribe in the Centothecoideae + Panicoideae clade is strongly supported; it is less clear whether it should be included in the Panicoideae, as in this treatment, or in the Centothecoideae.