Perennial 6-12 dm, glabrous to the silky calyces, freely branched into a diffuse panicle of loose spikes; lfls mostly 5-13, glaucous, 4-11 mm, narrow; spikes 5-30-fld, the fls ±2-ranked; bracts broadly ovate to obovate or truncate, enfolding and eventually falling with the cal; fls of subg. Parosela, white, 6-8 mm; cal-tube 3-3.5 mm, the triangular-aristate teeth 3.5-4.5 mm, very plumose, eventually spreading; stamens 9; fr 3-4 mm; 2n=14. Dry prairies and hillsides; w. Io. and w. Mo. to Mont., Colo., and N.M. July, Aug. (Parosela e.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
