Montana Field Guide

Perennials to 150 cm tall from robust rhizomes, these commony bearing tubers. Culms sharply triangular, often with concave sides, 3-13 mm thick towards the base. Leaves commonly 4-8, borne on the lower 1/2 of the stem; blades mostly 10-40 cm longer to 1 cm wide, the lower 1 or 2 sometimes reduced to bladeless sheaths. Leaflike involucral bracts usually 2 or 3, the longest one usually much exceeding the others and up to 34 cm long. Scalelike involucral bracts few to several, the larger ones with the green midrib exserted as a caudate awn. Spikelets 3-25 (rarely more), 10-35 mm long, 5-10 mm thick, all sessile in a compact cluster or with 1-4 additional clusters borne on peduncles to 6 cm long; scales tan or light brown, rarely dark brown, scarious, minutely hirtellous on the back, the firm midrib exserted as a mucronate awn, this commonly 1-3 times longer than the apical notch of the scale; perianth bristles few, minutely retrorse-barbellate, ca. 1/4-1/2(-3/4) as long as the achenes; styles 2-branched for ca. 1/3 the length. Achenes 2.5-4 mm long, lenticular, minutely cellular-reticulate (adapted from: Welsh et al., 1993, A Utah Flora, 2nd ed.).

Wet areas.