Rhizomatous. Stems erect, 20–50 cm. Leaves basal and cauline; blades 1–4 mm wide. Inflorescence of 2 to 4 well-separated spikes; the lowest bract greater than the inflorescence. Spikes unisexual; the upper 1 or 2 male, linear, 8–25 mm long; the lower female, ascending to arching, 1–2 cm long, pedunculate, short-cylindric. Perigynia ascending, tan to brown, elliptic, glabrous, 3–4.5 mm long with a distinct beak up to 0.5 mm long; stigmas 2 or rarely 3. Female scales ovate, brown to purplish with a pale midvein and margins, shorter than the perigynia. Achene 2- or rarely 3-sided, smaller than the perigynium (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Montana plants are variety
major Olney.
Wet, gravelly or shallow soil on margins of lakes, streams; valleys to subalpine, more common higher (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).