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Eragrostis
See list of 11 species in this genusEragrostis hirsuta (Michx.) Nees was reported from MA by Hitchcock and Chase (1950), but specimens are unknown. Reference: Peterson (2003a).
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1a. Plants extensively creeping by stolons, rooting at the nodes, forming mats; inflorescence 1–3.5 (–6) cm tall
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1b. Plants without stolons, the stems erect or ascending, sometimes decumbent at the base, not rooting at the nodes; inflorescence (3–) 4–40 (–60) cm tall
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2a. Leaf blades with elevated glands or glandular pits along the margin [Fig. 225]
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3a. Lemmas 1.5–2 mm long, lacking glandular pits along the keel (rarely with 1 or 2 obscure glands); sheaths pubescent on the margin and often near the apex; spikelets 4–7 (–11) mm long, with 7–12 (–20) florets
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3b. Lemmas 2–2.8 mm long, with 1–3 glandular pits along the keel; sheaths glabrous along the margin, sometimes pubescent near the apex; spikelets 6–20 mm long, with 10–40 florets
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2b. Leaf blades without glands along the margin
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4a. Plants perennial, with basal innovations, sometimes with short, knobby rhizomes
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5a. Plants with short, knobby rhizomes; inflorescence usually more than 40% of the total plant height; anthers 0.3–0.5 mm long; paleas falling with the lemmas during spikelet disarticulation
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5b. Plants without rhizomes; inflorescence usually less than 40% of the total plant height; anthers 0.5–1.2 mm long; paleas usually not falling with the lemmas and persistent on the rachilla during spikelet disarticulation
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6a. Lemmas 1.6–2.2 mm long, usually rounded on the abaxial surface and hardly keeled, with inconspicuous lateral veins; upper glume 1.3–2 mm long; caryopsis red-brown, opaque; ligules 0.2–0.4 mm long
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6b. Lemmas 1.8–3 mm long, keeled on the abaxial surface, with conspicuous lateral veins; upper glume 2–3 mm long; caryopsis light brown, transluscent; ligules 0.6–1.3 mm long
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4b. Plants annual, from fibrous roots, without basal innovations or rhizomes
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7a. Panicle large and diffuse, (10–) 15–45 (–55) cm tall and usually more than 50% of the total plant height; pedicels (4–) 5–25 mm long; spikelets with 2–5 (–7) florets
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7b. Panicle often smaller, 4–20 (–28) cm tall (up to 40 cm in E. mexicana) and usually less than 50% of the total plant height; pedicels 1–7 (–10) mm long; spikelets with 5–22 florets (with only 3–6 florets in E. frankii)
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8a. Spikelets with 3–6 florets, narrow-ovate to ovate in broad outline at maturity; plants often with glandular pits on the sheaths, below the nodes of the stem, on the rachis of the inflorescence, and/or on the panicle branches
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8b. Spikelets with 5–22 florets, narrow-lanceolate to broad-lanceolate in broad outline at maturity; plants lacking glandular pits (rarely with a few scattered glandular pits on the stems in E. pilosa)
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9a. Caryopsis with a shallow to deep, longitudinal groove running the entire length; leaf blades (2–) 3–7 (–9) mm wide
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9b. Caryopsis without a longitudinal groove; leaf blades 1–3 (–4.5) mm wide
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10a. Lower glume 0.3–0.6 (–0.8) mm long, less than ½ as long as the lowest lemma [Fig. 227]; branches of the panicle usually whorled at the 2 lowest nodes; paleas mostly deciduous with the lemmas and not persistent on the rachilla; lemmas with inconspicuous, lateral veins
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10b. Lower glume 0.5–1.1 mm long, ½ or more as long as the lowest lemma [Fig. 226]; branches of the panicle usually solitary or paired at the lowest 2 nodes; paleas persistent on the rachilla after the lemmas have fallen; lemmas with conspicuous, lateral veins
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Each photo represents one species in this genus.