Carex acutina L. H. Bailey; C. bishallii C. B. Clarke; C. hallii L. H. Bailey 1887, not Olney 1872; C. nudata var. anomala L. H. Bailey; C. suborbiculata Mackenzie; C. tenacissima Suksdorf

Plants cespitose, flowering from first-year shoots. Culms acutely angled, 35–70 cm, glabrous. Leaves: basal sheaths red-brown; sheaths of proximal leaves bladeless, scabrous, fronts with red-brown spots, prominently ladder-fibrillose, apex red-brown, U-shaped; blades hypostomic, 2–4 mm wide, papillose abaxially. Inflorescences: proximal bract shorter than inflorescence, 1–2 mm wide. Spikes erect; staminate 1–2; pistillate 2–4; proximal pistillate spike 2–4.5 cm × 5–6 mm, base cuneate. Pistillate scales dark red-brown to black, shorter than perigynia, apex obtuse, awnless. Perigynia ascending, pale brown with red-brown spots on apical 1/2, often blackish apically, 5–9-veined on each face, somewhat flattened, loosely enclosing achenes, thin-walled, ovoid or ellipsoid, 2.2–4 × 1.2–1.8 mm, leathery, dull, apex rounded or obtuse, papillose; beak red-brown, 0.1–0.3 mm. Achenes not constricted, dull. 2n = 70, 72.

Fruiting Jun–Jul. Dense tussocks in rocky streambeds; 0–1500 m; Calif., Oreg., Wash.

Carex nudata is also a member of the C. stricta group and is distinguished from sympatric members of the group by flowering from first-year shoots and having very narrow inflorescence bracts and somewhat elongated, heavily veined perigynia. It has a very distinctive growth form and habitat, dense tussocks among rocks in streambeds.