Montana Field Guide

Cool season, annual reeds. Stems scattered or in dense stands, rooting in mud, 1–3 m; sheath essentially hairless with overlapping margins; collar hairy; ligule membranous, 10–15 mm long. Leaves: blades 1–4 cm broad, flat and ascending. Inflorescences of large open panicles, 4–6 dm in length, the lower branches bearing pendulous staminate spikelets, the upper bearing appressed-ascending pistillate spikelets. Spikelets with one floret; staminate 6–8 mm long, pistillate 10–15 mm long (to 20 mm long in fruit), nearly round in cross-section, glumes of both spikelet types minute and consisting of a small cup just below point of disarticulation. Lemmas of pistillate spikelet hispid toward tip and tapered to an awn 6–40 mm long. Lemmas of staminate spikelets thin-textured and ephemeral. Disarticulation above glumes; unit of disarticulation the floret and fruit (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Marshes, lakes, and stream in fresh flowing water at lower elevations; often planted for waterfowl use (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).