28. Carex occidentalis L. H. Bailey, Mem. Torrey Bot. Club. 1: 14. 1889.
Plants without conspicuous rhizomes. Culms 25–90 cm, 1.6–2 mm wide basally, 0.6–0.7 mm wide distally. Leaves: sheaths tight, green, fronts hyaline; ligules less than 2 mm, as long as wide; widest leaf blades 1.5–2.5(–3) mm wide. Inflorescences with 4–10 spikes, 1.5–3.5 cm × 6–10 mm; proximal internodes as long as to slightly longer than proximal spikes, rarely 2 times as long; proximal bracts to 3 cm; spikes with 3–10 ascending to spreading perigynia. Pistillate scales brown with green, 3-veined center, ovate, 3.4–4 × 1.6–2 mm, body wider than and as long as perigynium, apex acuminate to short-awned, awn less than 1 mm. Anthers 2.5 mm. Perigynia brown, sometimes with green margins, faces obscurely veined, 2.5–4.5 × 1.5–1.9 mm, base of body somewhat spongy, margins serrulate distally; beak 0.6–1.3 mm, apical teeth 0.2–0.3 mm. Stigmas straight, 0.07 mm wide. Achenes elliptic-circular, 1.9–2 × 1.5–1.6 mm.
Fruiting spring–early summer. Dry grasslands, forests; 1200–3500 m; Ariz., Calif., Colo., Mont., Nev., N.Mex., N.Dak., S.Dak., Tex., Utah, Wyo.
There are questionable records from central Mexico of Carex occidentalis, which is otherwise endemic to the flora area.