Schoenoplectiella mucronata

Shortly rhizomatous perennial. Culms triquetrous, 50–100 cm high, to 8 mm diam. Leaves reduced. Inflorescence a head-like cluster of 3–25 spikelets, occasionally proliferating; Involucral bract 1–10 cm long. Spikelets oblong-ovoid, acute, 10–20 mm long 4–6 mm diam; glumes acute, shortly mucronate, striate, glabrous, pale red-brown to pale yellow-brown, 3.5–4 mm long; style 3-fid, rarely 2-fid; hypogynous bristles 5 or 6, retrorsely scabrous, unequal, slightly longer than the nut. Nut broad-obovoid, plano-convex or weakly trigonous, dark brown to black, smooth to rugulose, shining, about half the length of the glume, 1.7–2.2 mm long, 1.5–2 mm diam. Flowers spring–summer.