Herbs, annual or perennial, cespitose, rhizomatous or not, smooth, glabrous. Culms terete. Leaves all basal; sheaths green to stramineous, sometimes reddish proximally; ligules absent; blades rudimentary to exceeding culms. Inflorescences terminal, sometimes pseudolateral, capitate or solitary spikelet; spikelets 1-3(-15); involucral bracts 1(-2), spreading to erect, like foliage leaf blades. Spikelets: scales 8-25, spirally arranged, each subtending flower. Flowers bisexual; perianth absent; stamens 1-3; styles linear, 2-3-fid, base persistent, sometimes slightly enlarged. Achenes biconvex or trigonous, papillose or longitudinally ribbed.

Isolepis is difficult to delimit on a worldwide basis and has been included in Scirpus in the broad sense. Data derived from embryologic, genetic, and other studies led in recent years to the acceptance of Isolepis as a distinct genus (J. J. Bruhl 1995; P. Goetghebeur 1998; A. M. Muasya et al. 2001).