Calamagrostis koelerioides
Calamagrostis ×acutiflora
dense-pine reed grass, fire reedgrass
feather reed grass, Foerster's reedgrass
(26)60-85(120) cm, unbranched, slightly scabrous;
nodes 2-3(5).
135-210 cm, smooth to slightly scabrous, usually unbranched;
nodes about 3.
and collars usually scabrous, rarely smooth, glabrous;
ligules (1.5) 2-4.5(7) mm, truncate to obtuse, entire or sometimes lacerate;
blades (2)9-20(30) cm long, (2)2.5-4.5(8) mm wide, flat, slightly scabrous, adaxial surfaces glabrous or sparsely hairy.
and collars smooth;
ligules (1)2-7 mm, lacerate;
blades (5)11-63(71) cm long, (1)1.5-7.5(8) mm wide, flat or involute, usually scabrous, rarely smooth, adaxial surfaces glabrous or sparsely hairy.
(4)10-13(16) cm long, about 1 cm wide, contracted, erect to slightly nodding, often slightly interrupted towards the base, straw-colored or pale green to pale purple;
branches (1.1)2.8-4(6) cm, scabrous, spikelet-bearing to the base.
15-30 cm long, 0.75-1(3) cm wide, erect, contracted, pale green to purple;
branches about 6 cm, slightly scabrous, longer branches with spikelets on the distal 2/3, shorter branches with spikelets to the base.
(4)4.5-6(7) mm;
rachilla prolongations 1.5-2.5(3) mm, hairs 1.5-2 mm.
4-5 mm;
rachilla prolongations about 0.5 mm, hairs about 1.5 mm.
slightly keeled, keels smooth or slightly scabrous distally, lateral veins visible but not prominent, apices acute;
callus hairs 1.5-2 mm, 0.3-0.4 times as long as the lemmas, sparse;
lemmas (3.5)4-5(6) mm, 0.5-1.5 mm shorter than the glumes;
awns 4-5.5 mm, attached to the lower 1/10 – 1/5 of the lemmas, exserted, sometimes barely so, stout, distinguishable from the callus hairs, bent;
anthers 2-3.5 mm.
keeled, mostly smooth, slightly scabrous only on the keels, veins usually obscure, apices acute;
callus hairs 2-2.5 mm, 0.4-0.6 times as long as the lemmas, abundant;
lemmas 3-3.5 mm, 1-1.5 mm shorter than the glumes;
awns about 3.5 mm, attached to the lower 1/10 – 1/5 of the lemmas, exserted, slender, usually distinguishable from the callus hairs, bent;
anthers not observed.
= 28.
Calamagrostis koelerioides
Calamagrostis ×acutiflora
Calamagrostis koelerioides grows in mountain meadows, chaparral, and Jeffrey pine and blue spruce forests, and on talus slopes, dry hills, and ridges, occasionally on serpentine soils, at 50-2100 m. It extends from Washington south to southern California and east to Montana and western Wyoming.
Calamagrostis koelerioides is similar to C. rubescens (p. 723). The two have traditionally been distinguished by the presence of hairs on the leaf collars in C. rubescens, and their absence in C. koelerioides; a more reliable differentiation is the longer lemmas, glumes, and awns of C. koelerioides compared to C. rubescens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Calamagrostis ×acutiflora is a hybrid of European origin that is now widely planted as an ornamental, especially in dry sites and gardens throughout northern North America. The parents are C. arundinacea (L.) Roth and C. epigejos (p. 710); the hybrids are seed-sterile.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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