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Plants tufted, without creeping rhizomes. Culms to 45 cm × 0.2–1 mm. Leaves: distal leaf sheaths persistent, firm, distally tightly sheathing, apex acute. Spikelets orbicular to ovoid, 1–9 × 1–4 mm, apex rounded to acute; proximal scale without flower, not amplexicaulous; floral scales to 125, 11–14 per mm of rachilla, tightly appressed, dark red-brown to stramineous, ovate to elliptic, 0.8–3 × 0.6–2(–2.3) mm, membranous to cartilaginous, apex rounded to acute. Flowers: perianth bristles (0–)4–8, typically 7, red-brown, rarely whitish, vestigial to much exceeding tubercle, typically equaling achene, spinules few to dense; styles 2-fid. Achenes brown ripening to black, biconvex, orbicular to obpyriform, 0.5–1.1 × 0.3–0.7 mm, apex rarely constricted proximal to tubercle, very finely reticulate at 40X. Tubercles stramineous to whitish, umbonate to subconic, 0.2–0.4 × 0.2–0.5 mm, apex rounded to acute. 2n = 10.
A tufted annual with densely set culms from a relatively compact base and shallow root-system. Culms elongating to about 22 cm long when fruiting, 0.6-0.9 mm thick, irregularly ridged. Sheath grey above, purple below, ending in a short triangular acute lobe with thinner hyaline margin. Inflorescence orbicular to shortly ovoid, usually 3-4 mm long and 2.5-3.5 mm wide. Inflorescence-bracts scale-like, greenish, entirely covering the glumes in young buds. Glumes about 2 mm long, greyish below, brown above; midrib obscure, sometimes greenish; margin usually somewhat frayed without a distinct hyaline border; apex rounded. Perianth of about 7 glabrous, pink bristles overtopping the nutlet. Stamens 1-3, their filaments often persisting in fruit. Style 2-fid. Nutlet about 0.8 mm long and 0.6 mm wide, obovate, blackish-purple, smooth and shiny, appendage minute (0.1-0.2 mm long), low-conical, greyish-white.
Annual. Stems tufted, slender but rather rigid, erect or oblique, angular-striate, smooth, 5-40 cm by ½-1 mm. Sheaths appressed, purplish at the base, the uppermost with an oblique and more or less attenuate mouth. Spikelets globose to oblong-ovoid, very obtuse, terete, densely many-flowered, 4-8 by 3-3½ mm. Glumes membranous, appressed or obliquely ascending, broadly elliptic, broadly ovate or suborbicular, very obtuse, scarcely keeled, 1-nerved, ferrugineous with greenish keel and sides more or less tinged with purple, 1¼-2 by 1¼-1½ mm. Bristles 6-8, rather coarse, ferrugineous to brown, somewhat longer than the nut. Stamens 2-3; anthers linear-oblong, minutely apiculate, c. ½ mm. Style 2-fid. Nut biconvex, obovate, smooth, shining black, ¾-9/10 by 3/5-4/5 mm; epidermal cells very in-conspicuous, subquadrate. Style-base conical, usu-ally much depressed, about ⅓ as wide as the nut.
Rhizomes often coarse, the culms 3-10 idm. high, transversely septate, terete; spikelets 1-3 cm. long, 5-9 mm. thick, brown, the scales acutish; bristles equaling or longer than the achene, which is ellipsoid, biconvex to trigonous, granular, yellow-brown, the tubercle usually flattened, dark brown, elongate.
Medium sized, closely tufted plant up to 40 cm. high
Brownish, broadly ovate spikelets
