Panicum hirticaule |
Panicum obtusum |
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Mexican panicgrass, roughstalk witchgrass, roughstalk wltchgrass, woodland panic |
vine mesquite |
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Habit | Plants annual; glabrous or hispid, hairs papillose-based. | Plants perennial; usually from long slender stolons or shallow rhizomes with swollen, villous nodes. | ||||||||
Culms | 11-110 cm, erect to decumbent; nodes shortly hirsute or glabrous. |
20-80 cm, often in small clumps, compressed, erect or decumbent, glaucous; lower nodes pubescent; upper nodes glabrous. |
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Sheaths | shorter than the internodes, greenish to purplish, glabrous or with papillose-based hairs, ciliate on 1 margin, glabrous on the other; collars hirsute; ligules 1.5-3.5 mm, of hairs; blades 3-30 cm long, 3-30 mm wide, flat, usually hirsute or sparsely pubescent, hairs papillose-based, sometimes glabrous, bases rounded to cordate-clasping, margins ciliate, cilia papillose-based, apices acute. |
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Panicles | 9-30 cm long, 5-8 cm wide, erect or nodding, partially included to well-exserted, rachises glabrous or sparsely hispid basally; primary branches usually alternate to opposite, divergent, secondary branches and pedicels confined to the distal 2/3; pulvini inconspicuous; secondary branches appressed; pedicels 9-27 mm, appressed. |
5-15 cm long, 0.8-1.5 cm wide; branches 2-6, spikelike, erect, puberulent, 3-angled; ultimate branchlets 1-sided; pedicels paired, congested, shorter pedicels 0.1-1 mm, longer pedicels 1.5-2.5 mm. |
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Spikelets | 1.9-4 mm long, 0.8-1 mm wide, ovoid to almost spherical, often reddish-brown, glabrous, veins prominent, scabridulous, apices abruptly acuminate. |
2.8-4.4 mm, ellipsoid, terete to slightly laterally compressed, glabrous, obtuse. |
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Lower glumes | 1.3-2.4 mm, 1/2 - 3/4 as long as the spikelets, 3-5-veined; upper glumes 1.8-3.3 mm, 7-11-veined; lower florets sterile; lower lemmas similar to the upper glumes, 9-veined; lower paleas 0.4-0.9 mm; upper florets 1.5-2.4 mm long, 0.4-0.8 mm wide, ellipsoid, smooth or conspicuously papillate, shiny, stramineous, often with a lunate scar at the base. |
about 3/4 as long as the spikelets, 5- or 7-veined; upper glumes and lower lemmas equaling the spikelets, 5-9-veined; lower florets staminate; lower paleas 2.5-3.5 mm; upper florets puberulent at the bases and apices. |
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Lower | sheaths ascending, pubescent to pilose; upper sheaths glabrous; ligules 0.2-2 mm, membranous, truncate, irregularly denticulate; blades 3-26 cm long, 2-7 mm wide, ascending, firm, glaucous, sparsely pilose near the base, often scabrous on the margins, involute towards the apices. |
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2n | = 20, 36, 40. |
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Panicum hirticaule |
Panicum obtusum |
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Distribution |
AZ; CA; NM; NV; OK; TX; WA
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AR; AZ; CO; IL; KS; MO; NM; OK; TX; UT
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Discussion | Panicum hirticaule grows in rocky or sandy soils in waste places, roadsides, ravines, and wet meadows along streams. Its range extends from southeastern California and southwestern Texas southward through Mexico, Central America, Cuba, and Hispaniola to western South America and Argentina. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Panicum obtusum grows in seasonally wet sand or gravel, especially on stream banks, ditches, roadsides, wet pastures, and rangeland. Its range extends from the southwestern United States to central Mexico. Flowering is from May through October. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 460. | FNA vol. 25, p. 481. | ||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Agrostoidea > sect. Obtusa | ||||||||
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Subordinate taxa | ||||||||||
Synonyms | P. pampinosum | |||||||||
Name authority | J. Presl | Kunth | ||||||||
Web links |