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Calamagrostis

The genera Agrostis, Calamagrostis, and Deyeuxia are closely related and are defined by a combination of characters that are not unique to any genus (i.e., there exist several problematic, intermediate taxa). Based on the criteria used by Phillips and Chen (2003),  all our species of Calamagrostis, except C. epigejos, would be transferred to the genus Deyeuxia. However, a phylogeny based on DNA sequence data did not support the  monophyly of Deyeuxia. Reference: Marr et al. (2007).

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C. epigejos
1a. Pubescence of the callus (130–) 150–200 (–250)% as long as the lemma; rachilla not prolonged; glumes exceeding the lemmas by a distance of (1.5–) 2–3 (–4.5) mm; lemmas 2-nerved apical to the insertion of the awn
See list of 4 species in 1b
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1b. Pubescence of the callus 20–120 (–150)% as long as the lemma [Figs. 202,203]; rachilla prolonged behind the palea as a slender, pubescent bristle; glumes exceeding the lemmas by a distance of (0–) 0.1–2.1 mm; lemmas 4-nerved apical to the insertion of the awn
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  C. cinnoides
  2a. Awn attached well above the middle of the lemma; rachilla pubescent only at apex; caryopsis pubescent at apex
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  2b. Awn attached at or below the middle of the lemma [Fig. 203]; rachilla pubescent throughout; caryopsis glabrous
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    C. pickeringii
    3a. Callus hairs scant, up to 1 mm long, 20–30% as long as the lemma [Fig. 203];  awns straight
  - See list of 2 species in 3b
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    3b. Callus hairs moderate to copious, (1.5–) 1.7–3.5 (–4.5) mm long, 50–120 (–150)%  as long as the lemma [Fig. 202]; awns straight or bent
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      C. stricta
      4a. Panicle contracted and dense, (7–) 10–20 (–28) mm wide, the longer branches 1.4–5 (–9.5) cm long; pubescence of callus scant to moderate, concentrated in unequal lateral tufts, 20–75 (–100)% as long as the lemma; lemma awn minutely antrorsely scabrous throughout its length, delicate to stout, usually distinguishable from the callus hairs
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      C. canadensis
      4b. Panicle loose and somewhat open (less open in C. canadensis var. macouniana), (10–) 20–40 (–80) mm wide, the longer branches 2.7–6 (–12) cm long; pubescence  of callus moderate to dense, uniformly distributed, (70–) 90–120 (–150)% as long as the lemma; lemma awn smooth, as least in the basal half, delicate, often difficult  to distinguish from the callus hairs

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Show photos of: Each photo represents one species in this genus.