Tufted perennial 5-10 dm; lvs flat, 2-6 mm wide, elongate, the uppermost one more than 5 cm; infl mostly pale greenish, 10-25 cm, notably longer than thick, the smooth or sparsely scabrous branches forking near or below the middle, soon divaricate, the longest ones often less than 6(-12) cm; spikelets 1.8-2.8 mm; glumes subequal, scabrous on the midvein; lemma 1.3-2 mm, awnless or rarely with a very short, slender awn near the tip; palea obsolete; anthers 0.3-0.6 mm; 2n=42. Various habitats, usually in dry soil; Que. and N.S. to Minn., s. to Fla. and Tex. The foregoing description is based primarily on the widespread and highly variable var. perennans (A. oreophila; A. schweinitzii). Plants of bogs on the coastal plain from N.J. and Md. to Miss. have somewhat larger spikelets (2.7-3.5 mm) on short pedicels, aggregated in spike-like clusters toward the ends of the panicle-branches; these are var. elata (Pursh) Hitchc. (A. elata; A. altissima)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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From Flora of Indiana (1940) by Charles C. Deam

Infrequent to frequent in all parts of the state except in the prairie areas. This is a woodland species which seems to prefer a slightly acid soil and is found in black and white oak woods, pin oak woods, aspen thickets, at the bases of sandstone ledges, and rarely in prairie habitats or fallow fields. This species shows great variation which I assume to be the result of varying amounts of light, soil acidity, and nutriment.

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Indiana Coefficient of Conservatism: C = 2

Wetland Indicator Status: FAC

Diagnostic Traits: Tufted perennial; leaves to 5 mm wide, ligules >2.5 mm; panicles usually greenish, open, the branches forked at or below the middle; spikelets 1-flowered, to 2.2 mm long; glumes unequal, persisting after falling of floret; lemmas to 2 mm; palea absent or short.