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Calamagrostis

See list of 5 species in this genus

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).

  • 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
  • 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
    • 2a. Awn attached well above the middle of the lemma; rachilla pubescent only at apex; caryopsis pubescent at apex
    • 2b. Awn attached at or below the middle of the lemma [Fig. 203]; rachilla pubescent throughout; caryopsis glabrous
      • 3a. Callus hairs scant, up to 1 mm long, 20–30% as long as the lemma [Fig. 203]; 
awns straight
      • 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
        • 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
        • 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.