Isolepis

Slender annuals or more rarely perennials with erect nodeless culms, tufted or on slender rhizomes, with leaves basal and often reduced to sheaths; or elongate aquatic perennials with slender culms rooting at the nodes, sometimes floating. Involucral bracts 0–2, exceeding inflorescence, usually lowest erect and leaf-like, often falling early. Inflorescence a pseudolateral sessile head of one to several (occasionally numerous) spikelets with numerous flowers; glumes spirally arranged or rarely distichously arranged, mostly folded laterally when immature but spreading almost flat at maturity; hypogynous bristles or disc absent; stamens 1–3; style 2- or 3-fid, not enlarged at base, deciduous. Nut trigonous or lenticular or rarely subglobose, smooth or trabeculate or minutely verrucose or pitted but not rugose.