Pleuropogon californicus |
Pleuropogon |
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annual semaphoregrass, California semaphoregrass, semaphore grass |
pleuropogon, semaphore grass |
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Habit | Plants annual or perennial; cespitose, with many innovations, not rhizomatous, or with poorly developed rhizomes. | Plants annual or perennial; cespitose or rhizomatous. | ||||||||||||||||||||
Culms | 15-95 cm, erect or geniculate at the base, sometimes rooting at the lower nodes; nodes 3-6. |
5-160 cm, erect or geniculate at the base, glabrous; basal branching extravaginal. |
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Sheaths | glabrous; ligules 2-6 mm; blades 3-29 cm long, 3-8 mm wide, adaxial surfaces slightly scabridulous. |
closed almost to the top; ligules membranous; blades flat to folded, adaxial surfaces with prominent midribs. |
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Racemes | 8-35 cm, with 6-13 spikelets; internodes 1-6 cm; pedicels 1-5.5(9) mm, ascending to spreading. |
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Inflorescences | terminal, racemes, rarely panicles. |
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Spikelets | 15-60 mm, ascending to spreading, with 7-20(30) florets, lower florets bisexual, upper florets pistillate, terminal florets sterile. |
laterally compressed, with 5-20(30) florets, upper florets reduced; disarticulation above the glumes and beneath the florets. |
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Glumes | lanceolate to broadly ovate; lower glumes 1-4.5 mm; upper glumes 2-6.5 mm, 1-3-veined; rachilla internodes 1-2.8 mm long, 0.2-0.5 mm thick, with a glandular swelling at the base; lemmas 4.5-7.5 mm, 7(9)-veined, veins distinct, often prominent, apices truncate or emarginate, unawned or awned, awns to 11 mm; paleal keels scabridulous, each with a 0.5-2.5 mm triangular, winglike appendage, often denticulate beyond the appendage; anthers 2.5-4 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 | 2.5-3.1 mm. |
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Pleuropogon californicus |
Pleuropogon |
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Distribution |
CA
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AK; CA; OR; WA; BC; NF; NU; ON; QC; Greenland |
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Discussion | 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 | (Nees) Benth. ex Vasey | R. Br. | ||||||||||||||||||||
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