13. ISOLEPIS R. Brown, Prodr. 221. 1810.
[Greek, isos, equal, similar, and lepis, a scale]
S. Galen Smith
Scirpus Linnaeus sect. Isolepis (R. Brown) Grisebach
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.
Species 69 (4 in the flora): worldwide in cool-tropical and temperate regions, especially Africa and Australia.
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).
Muasya, A. M. 1998. Systematics of the Genus Isolepis R. Br. (Cyperaceae). Ph.D. thesis. University of Reading. Muasya, A. M. and D. A. Simpson. 2002. A monograph of the genus Isolepis R. Br. (Cyperaceae). Kew Bull. 57: 257–362. Muasya, A. M., D. A. Simpson, M. W. Chase, and A. Culham. 2001. A phylogeny of Isolepis (Cyperaceae) inferred using plastid rbcL and trnL-F sequence data. Syst. Bot. 26: 342–353.