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Hordeum

Hordeum marinum Huds. ssp. gussoneanum (Parl.) Thellung was reported from MA by Hitchcock and Chase (1950), but specimens are unknown. Reference: von Bothmer et al. (2007).

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H. vulgare
1a. Anthers 2–2.5 mm long; leaf blades 5–15 mm wide; rachis continuous and not disarticulating
See list of 4 species in 1b
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1b. Anthers 0.5–1.8 mm long; leaf blades 1.5–5 (–7) mm wide; rachis disarticulating
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  2a. Plants perennial; awns very slender
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    H. jubatum
    3a. Spikes arching or nodding [Fig. 235]; glumes 25–150 mm long including the awns; glume awns strongly bent outward and wide-ascending to spreading at maturity; fertile lemmas with an awn 10–60 mm long
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    H. brachyantherum
    3b. Spikes erect [Fig. 236]; glumes 7–20 mm long including the awns; glume awns  not or scarcely bent outward, erect to ascending; fertile lemmas with an awn 5–10 (–20) mm long
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  2b. Plants annual; awns stout
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    H. murinum
    4a. Glumes of the central spikelet of each triad with ciliate margins; auricles present at the summit of most leaf sheaths, well-developed, up to 8 mm long; body of fertile lemmas (6–) 7–10 mm long
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    H. pusillum
    4b. Glumes of the central spikelet of each triad with scabrous margins; auricles absent or poorly developed and very short; body of fertile lemmas 5–7 mm long

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