Culms 15-80 cm, erect. Leaves glabrous or pilose; lower sheaths usually retrorsely hirsute, sometimes glabrous; uppermost sheaths glabrous or scabridulous; ligules 0.8-3.5 mm, rounded to truncate, often lacerate and ciliate; blades flat; blades of lower leaves to 30 cm long, 1-8.5 mm wide; blades of
flag leaves 1-10 cm long, 1-5 mm wide. Panicles 3-20 cm; pedicels glabrous or scabrous-pubescent. Spikelets 4-7 mm. Glumes usually glabrous or scabrous on the keels and marginal veins; lower glumes 4-5(6.5) mm; upper glumes 4-5.5(7) mm; lemmas 1.8-3 mm, scabrous and ciliate apically, awns 2-4 mm; anthers 0.5-1.2 mm. Caryopses 1-1.5 mm. 2n = 14.
Vahlodea atropurpurea grows in moist to wet, open woods, forest edges, streamsides, snowbeds, and meadows, in montane to alpine and subarctic habitats. Plants from northwestern North America tend to have wider, more pubescent leaves and shorter lemma hairs than those elsewhere. They are sometimes treated as a distinct taxon, but the variation is continuous.
Perennial; culms solitary or in small tufts, 1-5 dm; lvs not densely crowded at base, the short blades erect, flat, 2-5 mm wide; ligule 1-3 mm; infl loose, 4-10 cm, its lowest branches usually paired; glumes purplish with brownish-scarious margins, equal, acuminate, 4.3-6.1 mm, twice as long as and generally concealing the lemmas, these obtuse or erose-truncate, minutely short-hairy above, long-hairy near the base; awn inserted near the middle, usually slightly bent, about equaling the glumes; anthers oval or oblong, 0.4-0.8 mm; 2n=14. Cold bogs and meadows; circumboreal, s. to the higher mts. of N.H. and N.Y., and to Colo. (Vahlodea a.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
