Perennials. Ligule membranous, ciliate. Inflorescence a cylindrical bilateral raceme with spikelets arranged alternately on opposite sides of a thickened fragile rachis, edgeways on and embedded in hollows of the rachis. Spikelets 1-flowered, dorsally compressed, falling at maturity with portion of rachis; rachilla prolonged. Lower glume minute or 0, except in uppermost spikelet; upper glume exceeding the rachis cavity and concealing the floret, appressed to rachis, coriaceous, 5-12-nerved, acute to caudately awned. Lemma 3-nerved, membranous, rounded, obtuse to acute. Palea ≤ lemma, 2-keeled. Caryopsis ellipsoid. Fig. 20.