in P. A. Rydberg, Fl. Rocky Mts., 138, 1060. 1917.
Plants densely cespitose. Culms to 25–60 (–100) cm, smooth. Leaves 2–6 mm wide. Inflorescences: proximal bracts shorter than or exceeding inflorescences; spikes oblong or clavate, 10–25 × 6–8 mm; proximal spikes separate, usually pendent, often long-pendunculate; distal ones overlapping, erect, contiguous, short-pendunculate; lateral 3–5 spikes pistillate; terminal spike gynecandrous, 1/4 or less staminate. Pistillate scales light to dark-brown, margins hyaline, lanceolate, typically equaling or longer, sometimes shorter and narrower than perigynia, midvein dark, same color as body, inconspicuous, frequently raised, prominent, apex acute to short-mucronate. Perigynia ascending, light to dark-brown with light-brown margins, veinless, obovate or circular, 3.5–4 × 2–3 mm, apex abruptly beaked, smooth; beak 0.3–0.5 mm, shallowly or deeply bidentate, smooth. Achenes filling proximal 1/2 or less of perigynia.
Phenology: Fruiting Jun–Sep.
Habitat: Stream margins in open forest, moist subpalpine and alpine meadows
Elevation: 2000–3700 m
Alta., B.C., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.
Intermediates between Carex epapillosa and C. heteroneura occur in California, Nevada, and Utah.