Annual or short-lived perennial 2-12 dm with tufted or solitary culms, the herbage glabrous to scabrous or pubescent; lvs flat, mostly 2-8 mm wide, mostly under 10 cm; ligules 1.5-3.5 mm, finely erose-ciliate; infl 0.5-2 dm, erect or nodding; glumes dissimilar, the first 1-3 mm, narrow, 0.1-0.3(-0.4) mm wide in side-view, with scabrous keel, the second 1.2-4.2 mm, broader, 0.5-1 mm wide in side-view; lemmas awnless, blunt to acute, smooth to scaberulous, the first 1.4-4.4 mm, the second a bit shorter; anthers small, mostly 0.3-0.7 mm; 2n=14. Moist meadows, streambanks, and shores of ponds or lakes; Nf. to Alas., s. to Fla., W.I., and Mex. Two vars. with similar ranges:
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent to local throughout the state. Its habitat varies from the crests of ridges in the "knobs" to low sand ridges and old lake and river bottoms. [Deam recognizes S. obtusata var. pubescens.] This is a form with the sheaths and upper and lower surface of the leaves pubescent. I have it from only the southern part of the state where it occurs in Crawford, Perry, and Posey Counties. I segregate this form from the species for the benefit of other workers who may be interested in the geographical distribution of the form.
FNA 2007, Gould 1980
Common Name: prairie wedgescale Duration: Perennial Nativity: Native Lifeform: Graminoid General: Perennial with stems 20-130 cm, sheaths open, glabrous or hairy, sometimes minutely roughened. Vegetative: Blades 5-14 cm long, 2-8 mm wide, usually flat, rarely slightly involute, scabrous or pubescent; ligules membranous 1.5-2.5 mm, erose-ciliate. Inflorescence: Contracted and dense panicles 5-15 cm long, 0.5-2 cm wide, usually erect, often spikelike, spikelets usually densely arranged, spikelets 2-3.5 mm; lower glumes less than one third as wide as the upper glumes, upper 1.5-2.5 mm, obtuse, rounded at broad apex, lemmas firm, glabrous or scabrous. Ecology: Found in flats, marshes, disturbed areas, often in moist soil along streams 3,000-8,000 ft (914-2438 m); flowers Notes: Similar to Koeleria cristata but differs in the smaller spikelets, non-puberulent inflorescence axis, and the ligule with a notch in the middle. Ethnobotany: Unknown Etymology: Sphenopholis is from Greek sphen for wedge and pholis for scale, referring to the shape of the upper glume, while obtusata means blunted. Synonyms: Aira obtusata, Spenopholis obtusata var. lobata, S. obtusata var. pubescens Editor: SBuckley, 2010