Plants densely or loosely cespitose; rhizomes short, thick. Culms to 100 cm. Leaves: blades 5-20 mm wide. Inflorescences with 4-6 spikes; peduncles of proximal spikes exserted more than 1 cm; proximal bracts with blade (13-) 17-35(-55) mm, sheaths conspicuously expanded to mouth, 21-35(-42) mm, mouth with wide purple band, usually shallowly U-shaped, greater than 2 mm wide. Lateral spikes pistillate, purple to dark brown, pendent, (17-)19-30 × 6-9 mm. Terminal spike staminate, ± erect or, occasionally, pendent, 9-19 × 4.5-9 mm. Pistillate scales glossy dark purple with narrow hyaline margins,often gold adaxially, usually ovate, apex obtuse to long-tapered (rarely ciliate-awned), glabrous. Staminate scales dark reddish purple with pale midvein and narrow, scarious margins, ovate to elliptic, 3.2-4.1 × 1-2 mm, apex usually obtuse, occasionally short-awned. Anthers (1.8-)2.4-4 mm. Perigynia ascending, dark purple, veins indistinct, elliptic or ovate to broadly ovate, 4-5.3 × 1.7-2.5 mm, with flat margins more than 1/2 mature achene width, glabrous; beak 1-2 mm, apex dark purple to blackish, glabrous, distance from beak tip to achene apex greater than 2 mm. Achenes obovoid, 1.5-2.2 × 0.85-1.2 mm.

Fruiting summer. Wet meadows; 2100-2800 m; Calif., Idaho, Mont.