Flora of North America species comparison

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Calamagrostis koelerioides

Calamagrostis rubescens

dense-pine reed grass, fire reedgrass

pine reed grass, pinegrass
Habit Plants without sterile culms; often densely cespitose, with rhizomes 2-6 cm long, 2-4 mm thick. Plants sometimes with sterile culms; sometimes loosely cespitose, usually with rhizomes 15+ cm long, 1.5-2 mm thick.
Culms

(26)60-85(120) cm, unbranched, slightly scabrous;

nodes 2-3(5).

(50)60-100(105) cm, unbranched, usually smooth, rarely slightly scabrous beneath the panicles;

nodes (1)2-3(4).
Sheaths

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.

smooth or slightly scabrous;

collars often hairy, rarely glabrous;

ligules (2)3-5(6) mm, truncate to obtuse, often lacerate;

blades (6)8-40(42) cm long, (1)2-5(8) mm wide, usually flat, abaxial surfaces smooth or slightly scabrous, adaxial surfaces smooth or scabrous, glabrous or sparsely hairy.
Panicles

(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.

(5)6-15(25) cm long, (0.7)1.5-2(2.7) cm wide, contracted to somewhat open, erect, usually greenish, infrequently purplish;

branches (1.2)2-4(10) cm, usually slightly scabrous, rarely densely long-scabrous, spikelet-bearing to the base.
Spikelets

(4)4.5-6(7) mm;

rachilla prolongations 1.5-2.5(3) mm, hairs 1.5-2 mm.

(3)4-4.5(5.5) mm;

rachilla prolongations 0.6-1.5(2) mm, hairs 1.2-2 mm.
Glumes

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.

rounded to slightly keeled, mostly smooth, keels rarely slightly scabrous, lateral veins usually obscure, rarely prominent, apices acute;

callus hairs (0.5)1-1.5(2.5) mm, 0.2-0.5(0.7) times as long as the lemmas, sparse;

lemmas 2.5-3.5(4) mm, (0.5)1-2 mm shorter than the glumes;

awns 2.8-3.5(4.5) mm, usually attached to the lower 1/5 of the lemmas, rarely higher, exserted, stout and readily distinguished from the callus hairs, strongly bent;

anthers (1)1.3-2(2.6) mm.
2n

= 28.

= 28, 42, 56.

Calamagrostis koelerioides

Calamagrostis rubescens
Distribution
from FNA
CA; ID; MT; OR; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC; MB; SK
[WildflowerSearch map]
[BONAP county map]
Discussion

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 rubescens grows at 50-2800 m, usually in open montane pine or aspen forests and parklands, infrequently in sagebrush steppes, chaparral, and meadows. It is primarily a species of interior western North America, although it reaches the Pacific coast in southern California. The distribution extends from central British Columbia and Alberta east to the Cypress Hills of eastern Alberta and the Pasquia and Cub hills of Saskatchewan, south to western California, Nevada, northeastern Utah, and central Colorado. It is considered threatened in Saskatchewan.

Calamagrostis rubescens is similar to C. koelerioides (p. 721). The two have traditionally been distinguished by the presence of hairs on the leaf collars of C. rubescens, and their absence from C. koelerioides; a more reliable differentiation is the shorter lemmas, glumes, and awns of C. rubescens. Calamagrostis rubescens and C. porteri (p. 721) appear to be closely related. They may be part of the general phenomenon of eastern and western vicariants.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 24, p. 720. FNA vol. 24.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Calamagrostis Poaceae > subfam. Pooideae > tribe Poeae > Calamagrostis
Sibling taxa
C. bolanderi, C. breweri, C. cainii, C. canadensis, C. cinnoides, C. deschampsioides, C. epigejos, C. foliosa, C. howellii, C. lapponica, C. montanensis, C. muiriana, C. nutkaensis, C. ophitidis, C. perplexa, C. pickeringii, C. porteri, C. purpurascens, C. rubescens, C. scopulorum, C. sesquiflora, C. stricta, C. tacomensis, C. tweedyi, C. ×acutiflora
C. bolanderi, C. breweri, C. cainii, C. canadensis, C. cinnoides, C. deschampsioides, C. epigejos, C. foliosa, C. howellii, C. koelerioides, C. lapponica, C. montanensis, C. muiriana, C. nutkaensis, C. ophitidis, C. perplexa, C. pickeringii, C. porteri, C. purpurascens, C. scopulorum, C. sesquiflora, C. stricta, C. tacomensis, C. tweedyi, C. ×acutiflora
Name authority Vasey Buckley
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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