Perennial from tubers and underground runners. Tubers are bitter to taste. Stems triangular, from 4 inches to 1 ½ feet tall. Leaf blades 1/16 to ¼ inch wide, basal blades usually shorter than the seedhead. Leaf tips abruptly tapering to a sharp point, often described as “boat shaped”. Seedheads with 2-4 inconspicuous leaves below. Seedheads reddish or reddish purple, 1 ¼ to 3 ¾ inches long and 1 ½ to 2 ¾ inches wide. Seedheads with several unequal stalks each bearing 3 to 9 thin, spreading or ascending spikes. Seed is grayish, less than 1/16 inch long, and three-angled. Propagation is primarily by tubers and runners, but occasionally by seed.