Aristida mobrii |
Aristida schiedeana |
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single threeawn |
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Habit | Plants perennial; cespitose. | |
Culms | 30-120 cm, erect, unbranched. |
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Leaves | basal and cauline, pale green, sometimes glaucous; sheaths longer or shorter than the internodes, glabrous except at the summit; collars densely to sparsely pilose or glabrous; ligules less than 0.5 mm; blades 8-30 cm long, 1-2 mm wide, usually flat, often curled at maturity. |
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Inflorescences | paniculate, 10-30 cm long, (4)8-26 cm wide; rachis nodes with straight hairs, hairs to 0.8 mm; primary branches 6-16 cm, abruptly spreading to divaricate, stiff to lax, with axillary pulvini, usually not spikelet-bearing below midlength. |
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Spikelets | appressed, rarely spreading. |
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Glumes | 1(3)-veined, brown or purple at maturity, acuminate; lower glumes 6-13 mm; upper glumes equaling or to 4 mm shorter than the lower glumes; calluses 0.8-1.2 mm; lemmas 10-15(17) mm, terminating in a strongly twisted, 2-4 mm awnlike beak, junction with the awns not conspicuous; awns not disarticulating at maturity; central awns 5-12 mm, markedly bent near the base; lateral awns absent or to 1(3) mm, erect; anthers 1.2-2.2 mm, brownish. |
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Caryopses | 6-8 mm. |
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2n | = 22, 44. |
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Aristida mobrii |
Aristida schiedeana |
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Distribution |
AZ; CA; NM; TX
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Discussion | Aristida schiedeana grows on rocky slopes and plains, generally in pinyon-juniper, oak, or ponderosa pine communities. Plants from the southwestern United States and northern Mexico belong to A. schiedeana var. orcuttiana (Vasey) Allred & Valdes-Reyna, in which the lower glumes are usually glabrous and longer than the upper glumes, and the collar and throat are usually glabrous. Aristida schiedeana var. schiedeana grows in Mexico, Guatemala, Nicaragua, and Honduras, and has puberulent, equal glumes and pilose collars and throats. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 25, p. 323. | |
Parent taxa | ||
Sibling taxa | ||
Name authority | Trin. & Rupr. | |
Web links |