R. Brown

Prodr., 221. 1810.

Etymology: Greek, isos, equal, similar, and lepis, a scale
Synonyms: Scirpus sect. Isolepis (R. Brown) Grisebach
Treatment appears in FNA Volume 23. Treatment on page 137. Mentioned on page 8, 138.

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.


Worldwide in cool-tropical and temperate regions, especially Africa and Australia.


Species 69 (4 in the flora).

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).


1 Spikelets with scales markedly gibbous, often clasping shed achenes, colorless to stramineous, or orangish, or greenish; achenes acutely equilaterally trigonous; leaf sheaths green to stramineous or brown. > 2
1 Spikelets with scales neither gibbous nor clasping shed achenes, usually at least partly orange- to red-brown or blackish; achenes compressed-trigonous or thickly plano-convex; leaf sheaths usually reddish proximally. > 3
2 Scales from middle of spikelet 1.8–2 mm, with awns 0.2–0.5 mm; achenes 1–1.5 mm. Isolepis carinata
2 Scales from middle of spikelet 1–1.2 mm, with mucros to 0.1 mm; achenes 0.7–0.9 mm. Isolepis pseudosetacea
3 Achenes papillose, not ribbed; culms, leaves, and involucral bracts not orange-punctate or sheaths sparsely so. Isolepis cernua
3 Achenes not papillose, prominently longitudinally ribbed at 10X and minutely transversely ridged at 20–30X; culms, leaves, and involucral bracts orange-punctate at 10– 15X. Isolepis setacea
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