Pleuropogon refractus |
Pleuropogon |
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nodding false semaphore grass, nodding semaphore grass |
pleuropogon, semaphore grass |
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Habit | Plants perennial; not cespitose, rhizomatous. | Plants annual or perennial; cespitose or rhizomatous. | ||||||||||||||||
Culms | (85)100-150 cm, erect. |
5-160 cm, erect or geniculate at the base, glabrous; basal branching extravaginal. |
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Sheaths | glabrous or pubescent, sometimes scabridulous; ligules 2-7 mm; blades 10-40 cm long, 5-14 mm wide, apices acute or acuminate and sharply mucronate, flag leaves often reduced to spinose tips. |
closed almost to the top; ligules membranous; blades flat to folded, adaxial surfaces with prominent midribs. |
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Racemes | (10)20-35 cm, with 6-14 spikelets; internodes 2-5.6(8) cm; pedicels 2-3 mm long, reflexed at maturity. |
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Inflorescences | terminal, racemes, rarely panicles. |
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Spikelets | (20)25-28 mm, pendent, with 7-14 florets, usually all but the terminal floret bisexual. |
laterally compressed, with 5-20(30) florets, upper florets reduced; disarticulation above the glumes and beneath the florets. |
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Glumes | frequently scabrous, apices obtuse, sometimes erosely notched; lower glumes 3-6 mm; upper glumes 4-7(8.3) mm, 3-veined; rachilla internodes 2-3 mm long, about 0.1 mm thick, bases sometimes weakly differentiated into a glandular swelling; lemmas 8-10 mm, faintly 7(9)-veined, lateral veins occasionally prominent, apices truncate, sometimes toothed, awned, awns (5)9-20 mm; paleal keels each with a 0.2-0.6(1) mm triangular appendage; anthers 3.5-4 mm. |
unequal to subequal, shorter than the adjacent lemmas, membranous to subhyaline, margins scarious; lower glumes 1-veined; upper glumes 1-3-veined; rachilla internodes in some species swollen and glandular basally, the glandular portion turning whitish when dry; calluses rounded, glabrous; lemmas thick, herbaceous to membranous, 7(9)-veined, veins parallel, margins scarious, apices scarious, entire or emarginate, midvein sometimes extended into an awn, awns straight; paleas subequal to the lemmas, 2-veined, keeled over each vein, keels winged, with 1 or 2 awns or a flat triangular appendage; lodicules 2, completely fused; anthers 3, opening by pores; ovaries glabrous, x = 8, 9, 10. |
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Caryopses | 4.5-6 mm. |
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2n | =32, 36. |
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Pleuropogon refractus |
Pleuropogon |
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Distribution |
CA; OR; WA; BC
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AK; CA; OR; WA; BC; NF; NU; ON; QC; Greenland |
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Discussion | Pleuropogon refractus grows in wet meadows, riverbanks, and shady places, from sea level to about 1000 m. Its range extends from British Columbia south to California. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Pleuropogon is a genus of five hydrophilous species, one circumboreal in the arctic, the other four restricted to the Pacific coast of North America, extending from southern British Columbia to central California. The Pacific coast species are sometimes treated as a separate genus, Lophochlaena Nees, but are here regarded as constituting a subgenus of Pleuropogon. The flat, triangular paleal appendages differ from bristly or flattened awns in being wider at the base, and smooth rather than scabrous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24. | FNA vol. 24, p. 103. | ||||||||||||||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Meliceae > Pleuropogon | Poaceae > subfam. Pooideae > tribe Meliceae | ||||||||||||||||
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Name authority | (A. Gray) Benth. ex Vasey | R. Br. | ||||||||||||||||
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