Annual. Stems very slender, densely tufted, weak, strongly compressed, ribbed, smooth, leafy at the base, 10-30 cm by ¾-1¼ mm. Leaves shorter than the stems, flat, weak, rather abruptly acuminate. glabrous, scabrid on the margins in the upper part, 1-2 mm wide; ligule a dense fringe of short hairs. Inflorescence decompound, very loose, diffuse, with many spikelets, 3-7 cm long. Involucral bracts 2-4, erect, shorter than to as long as the inflorescence, the lowest up to 4 cm. Primary rays slender, compressed-angular, smooth or scabrid at the top, up to 5 cm. Spikelets solitary, very small, ovoid to oblong-lanceolate, angular, acute, few-to several-flowered, ferrugineous, 2-4 by 1 mm; rachilla winged. Glumes spiral, membranous, broadly ovate, acute, mucro-nulate (mucro often slightly excurved), acutely keeled, glabrous, with 3-nerved keel and nerveless sides, c. 1 by 1 mm. Stamen 1 (see Notes); anther oblong, ¼ mm long. Style triquetrous, pyramidally thickened at the base, glabrous, c. ½ mm long; stigmas 3, somewhat shorter than the style. Nut trigonous with prominent angles and somewhat convex sides, obovoid, subsessile, umbonulate, finely lineolate by the transversely oblong-linear epidermal cells superposed in 4-6 vertical rows on each face, smooth or sparsely and minutely verruculose, whitish, ½-3/5 by ⅓-2/5 mm.
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Annuals. Culms densely tufted, 10-30 cm tall, 0.7-1.3 mm thick, flatly 3-angled, smooth. Leaves basal, few; sheath light straw-colored to pale brown; ligule ciliate; leaf blade linear, to 18 cm × 1.5-5 mm, flat, apical margin scabrid. Involucral bracts 3 or 4, basalmost leaflike and to 4 cm. Inflorescence a decompound anthela, 3-6 × 3-6 cm, lax; primary rays 2-5, 1-5 cm, unequal, apically scabrous. Spikelets numerous per inflorescence, solitary, rust-colored, narrowly ovoid, 2-3 × 1-1.2 mm, slightly angular, sublaxly 5-10-flowered, apex acute. Glumes numerous, spirally imbricate, light rust-colored with pale brownish margins, ovate, 1-2 mm, membranous, 3-veined forming an abaxial keel, apex mucronate. Stamens 1 or 2; anthers 0.2-0.3 mm. Style 3-sided, glabrous, basally dilated; stigmas 3. Nutlet subsessile, light straw-colored, obovoid, 0.4-0.5 × 0.3-0.4 mm, ± smooth or with scattered verrucae and slightly cancellate with transversely oblong cells.
Annual herb, up to 400 mm tall. Leaf sheaths not spongy, markedly compressed at mouth. Ligule a line of densely packed, fine, white hairs. Blades not reduced to minute apiculi. Glumes, brown.
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