Carex sect. Collinsiae
in N. L. Britton et al., N. Amer. Fl. 18: 425. 1935.
Plants cespitose, short-rhizomatous. Culms purple-brown at base. Leaves: basal sheaths not fibrous; sheath fronts membranous only in short obtriangular region at mouth; blades V-shaped in cross section when young, glabrous. Inflorescences racemose, with 3–5 spikes; proximal bracts leaflike, sheathing, sheath 4+ mm, longer than diameter of stem; lateral spikes androgynous or pistillate, pedunculate, prophyllate; terminal spike staminate. Proximal pistillate scales 1-veined, apex cuspidate or awned. Perigynia spreading or reflexed, many-veined, stipitate, subulate, round in cross section, base tapered, apex tapered to beak, glabrous; beak straight, 3–4 mm, bidentate, teeth reflexed. Stigmas 3. Achenes linear-oblong, smaller than bodies of perigynia; style persistent.
e North America.
Carex collinsii belongs to a monotypic section of uncertain relationships; it has been placed within sections Folliculatae and Lupulinae and considered closely related to section Microglochin. Carex collinsii lacks the entire beak and protruding rachilla characteristic of the latter section. The almost hooked teeth of the perigynium and obliquely cleft beak are not found in any other species of Carex. No intersectional hybrids are reported.