Ctenium

Plants usually perennial, sometimes annual; cespitose or rhizomatous. Culms 10-150 cm, simple. Leaves often aromatic; ligules membranous, sometimes ciliate; blades flat or convolute, upper blades reduced. Inflorescences terminal, panicles of 1-3 strongly pectinate branches, usually exceeding the upper leaves; branches usually falcate, if more than 1, digitately arranged, axes crescentic in cross section, with 2 rows of solitary, subsessile spikelets. Spikelets strongly divergent, laterally compressed, with 2 well-developed sterile or staminate florets below the single bisexual floret, reduced sterile or staminate florets also present beyond the bisexual floret; disarticulation above the glumes. Glumes unequal; lower glumes shorter than the upper glumes, 1-veined, keeled; upper glumes 2-3-veined, awned dorsally; lemmas thin, 3-veined, entire or bidentate, awned, awns dorsal, attached just below the lemma apices, or terminal; lodicules 2, glabrous; anthers 3 in bisexual florets, 2 in staminate florets; styles 2. Caryopses ellipsoid. x = 9. Name from the Greek ktenion, a little comb, an apt description of the inflorescence branches.

Spikelets sessile, pectinately arranged in 2 rows on one side of a flat rachis, articulated above the glumes, with several lemmas, of which only one is fertile; first glume small, nearly hyaline, 1-veined; second glume nearly as long as the spikelet, firm on the round exposed back, thin on the sides, conspicuously 3-veined, the midvein prolonged into a stout divergent awn from near the middle of the glume; lemmas thin, obscurely 3-veined, the two lower empty, without paleas, the third with a palea and a fl, the upper 1-3 sterile and much reduced; midvein of the lower 3 lemmas prolonged into an awn from below the tip; perennials with narrow lvs, membranous ligule, and a solitary, usually curved spike. 20, New World and Afr.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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