Plants densely cespitose. Culms often lax, supported by other vegetation, 27-105 cm. Leaves: sheaths white-hyaline or green-veined with central white-hyaline strip, summits U-shaped to rounded, sometimes prolonged beyond collar; distal ligules 1.5-5.5 mm; blades 3-6 per fertile culm, 12-65 cm × 1.3-3.7(-4.6) mm. Inflorescences dense to open, green and brown, gold and brown, or brown, 1.3-3.5 cm × 7-23 mm; proximal internode 2-3(-4.5) mm; 2d internode 1-3 mm; proximal bracts bristlelike or rarely leaflike, longer than inflorescences. Spikes 4-11, densely aggregated, at least proximal 1-3 distinct, ovoid to broadly ovoid, 6-12.3 × 3.8-9.1 mm; base rounded; apex acute to rounded. Pistillate scales brown, red-brown, or coppery, with whitish, green, or pale brown midstripe, ovate, (3.2-)3.5-4.5 mm, shorter, narrower than, or covering perigynia, margin often indistinct, white, 0-0.4 mm wide, apex ± obtuse or rarely short-awned. Perigynia ascending to spreading, straw colored or gold to coppery, conspicuously (0-)5-9-veined abaxially, conspicuously 0-6-veined adaxially, veins not reaching top of achene, ovate to broadly ovate, plano-convex to biconvex, (2.9-)3.5-4.7(-5.7) × 1.2-1.7(-2.2) mm, 0.5-0.75 mm thick, ± leathery, margin flat, including wing 0.2-0.4 mm wide, ciliate-serrulate at least on distal body, with metallic sheen; beak often brown to dark brown at tip or white-hyaline, cylindric, unwinged, abaxial suture inconspicuous, distance from beak tip to achene 1.5-2.2(-2.6) mm, ± entire for (0.3-) 0.4-0.8 mm. Achenes broadly ovate to quadrate, 1.3-2.1 × 1-1.5(-1.7) mm, 0.5-0.6 mm thick.

Fruiting spring-summer. Meadows, swales, moist places, roadsides, along the coast and in Coast Ranges; 0-900 m; Calif.

Carex subbracteatais very similar to and perhaps conspecific with C. gracilior (R. Whitkus 1988).