Rhizomatous, 1-4 dm, the culms in small tufts erect from a decumbent base; lvs flat or folded, erect, 1-3 mm wide, much shorter than the stems; ligule ovate, 1-3 mm; infl broadly ovoid, loosely branched, the branches paired, slender, spreading; spikelets ovate to oblong, 5-8 mm, 3-6-fld; first glume lanceolate, acute, 2.6-5.2 mm, the second ovate, 3-5.5 mm; lemmas 3.4-5.5 mm, usually purple, strongly suffused with orange below the scarious tip, pubescent on and between the rather obscure veins, especially toward the base, with or without a small web; anthers 1.5-2.3 mm; 2n=38, 56, 72, 76. Circumboreal in cold meadows and on cold, stony slopes, s. to the Rocky Mts. and reputedly to N.S. and the mts. of Me. and N.H. (P. alpigena, at least as to our plants)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.