Linnaea 37: 527. 1872.
Plants perennial, cespitose, 10–40 cm, wiry; rhizomes absent. Culms erect to spreadingascending, leafybased, trigonous or compressed, ribbed. Leaves exceeded by scape; blades narrowly linear to filiform, 0.2–2 mm wide, apex tapering, trigonous. Inflorescences terminal, solitary, headlike, dense, white, leafyinvolucrate, hemispheric to globose, 0.5–1.5 cm wide; involucral-bracts (0–) 1–4, ascending to recurved, green, (0.7–) 2–5 (–6) cm × 0.2–2 mm. Spikelets white, ovoid, 5–7 mm; fertile scales several, boatshaped, 2.5–3.5 mm, keel curved, not sharp. Flowers: perianth absent. Fruits 0.8–1 mm; body yellow to near black, broadly pyriformobovoid, tumidly lenticular, 0.5–0.8 × 0.5–0.8 mm, margin narrow, flowing into tubercle; surfaces transversely sharply wavyrugose, ridges bordered by rows of fine, linear, vertical lattices; tubercle depressedtriangular, lunate-based, shortbeaked 0.2 (–0.3) mm, graycrustaceous.
Phenology: Fruiting spring–fall.
Habitat: Low, open, moist to wet, basic substrates of fens, meadows, seeps, and shores, limestone districts
Elevation: 0–500 m
Rhynchospora nivea, of the “Dichromena” of North America, is the smallest fruited and most slender and has the fewest and shortest involucral bracts (in some plants the bract is entirely absent). Involucral bracts of R. nivea are almost entirely green.
"wider" is not a number.