Calamagrostis rubescens
Robert L. Carr

Flora of Oregon

Plants (50)60–100(105) cm tall; rhizomatous, sometimes appearing loosely cespitose; rhizomes to 15 cm long or longer, 1.5–2 mm thick.

Leaves sheaths smooth or slightly scabrous, rarely pubescent; collars usually pubescent, rarely glabrous; blades (6)8–40(42) cm × (1)2– 5(8)mm, usually flat; lower surfaces smooth or slightly scabrous; upper surfaces smooth, scabrous or sparsely pubescent.

Inflorescences (5)6–15(25) × 1–2.5 cm, contracted to somewhat open, erect, usually greenish to straw-colored, uncommonly purplish; branches (1.2)2–3(6) cm, slightly scabrous, rarely densely long-scabrous, spikelet-bearing to the base.

Glumes (3)4–4.5(5.5)mm, rounded to slightly keeled.

Calluses with hairs 0.5–1.5(2.5)mm, 20–50(60)% as long as the lemmas, sparse.

Lemmas 2.5–4 mm, 0.5–2 mm shorter than the glumes; lemma awns 2.8–3.5(4.5) mm, usually attached to the lower 20% of the lemma, rarely higher, exserted from the spikelet, stout, readily distinguished from the callus hairs, strongly bent.

Anthers 1.2–2.6 mm.

2n=28, 42, 56.

Dry montane conifer forests. 800–2500m. BW, Casc, ECas, Lava. CA, ID, NV, WA; north to British Columbia, northeast to Saskatchewan, southeast to CO. Native.

Calamagrostis rubescens is a common community dominant with Carex geyeri in dry montane conifer forests east of the Cascades. Though it is usually identified by the curly, spreading hairs on its leaf collars, some collars may be glabrous. Examining several leaves will usually reveal pubescent collars somewhere on the plant. Similar C. koelerioides has glabrous collars and longer lemmas and awns. Established populations rarely flower, but low-intensity forest fires stimulate vigorous flowering.

Photo images

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Herbarium specimens

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