Kendrick L. Marr Richard, J. Hebda and Craig W. Greene†
Plants sometimes with sterile culms; loosely cespitose, with rhizomes 7+ cm long, 1 mm thick. Culms (10)15–45(60) cm, unbranched, smooth beneath the panicles; nodes 1–2. Sheaths and collars smooth; ligules (0.5)1–2.5(3) mm, truncate to obtuse, usually entire, sometimes lacerate; blades (2)3–8(15) cm long, (1)1.5–2.5(3) mm wide, flat or somewhat involute, abaxial surfaces smooth, adaxial surfaces smooth or slightly scabrous, glabrous or sparsely hairy. Panicles 3–10(12) cm long, 1–4.5 cm wide, pyramidal, open, erect, green to dark purple; branches (2)2.5–4(5.5) cm, spreading, smooth or sparsely scabrous, spikelets usually confined to the distal 1/2. Spikelets 4–5.5(7) mm; rachilla prolongations 1–2 mm, hairs (0.5)1–1.5 mm. Glumesrounded, usually smooth, sometimes scabrous along the midvein, lateral veins mostly obscure, apices acute to acuminate; callus hairs 2–3 mm, 0.4–0.7 times as long as the lemmas, abundant; lemmas 3.5–4.5(5.5) mm, 0.5–1(1.5) mm shorter than the glumes; awns 3–4.5(5.5) mm, attached to the lower 1/3–1/2 of the lemmas, usually exserted, rarely included within the glumes, slender but distinguishable from the callus hairs, weakly to strongly bent; anthers (1.5)2–2.5 mm. 2n = 28.
Calamagrostis deschampsioides is a halophyte that grows, in the Flora region, on coastal dunes and beach ridges, gravel beaches, and in brackish coastal marshes, sometimes with Carexlyngbyei, at or near sea level. Its distribution is circumboreal, extending in North America from the islands of the Bering Sea and coastal Alaska, including the panhandle as far south as 56º N latitude, across the arctic coast to Hudson Bay and northern Labrador. It also extends from the arctic coast of Europe to Siberia and Japan. The alpine habitat reported for the Japanese plants suggests that they might belong to a different taxon.