Aristida adscensionis |
Aristida californica |
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sixweeks three-awn, three awn |
California three-awn, Mojave three-awn |
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Habit | Plants short- to long-lived annuals. | Plants perennial; sometimes flowering the first year. | ||||
Culms | (3)10-50(80) cm, often highly branched above the base. |
10-40 cm, highly branched above the base in age; internodes glabrous or pubescent, sometimes nearly lanose. |
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Leaves | cauline, glabrous; sheaths shorter than the internodes, not disintegrating into threadlike fibers; ligules 0.4-1 mm; blades 2-14 cm long, 1-2.5 mm wide, flat to involute. |
cauline; sheaths shorter than the internodes, glabrous or puberulent; collars glabrous or pubescent at the sides; ligules 0.5-1 mm; blades usually less than 6 cm long, 0.5-1 mm wide, pale green, involute, glabrous or puberulent abaxially. |
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Inflorescences | panicles, 5-15(20) cm long, 0.5-3 cm wide, often interrupted below; nodes glabrous or with straight, less than 0.5 mm hairs; primary branches 1-4 cm, erect to ascending, without axillary pulvini, with 3-8 spikelets. |
paniculate or racemose, 5-10 cm long, 1-2 cm wide, with few spikelets; rachis nodes glabrous or with straight hairs; primary branches 1-2 cm, appressed, without axillary pulvini. |
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Spikelets | crowded. |
appressed. |
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Glumes | unequal, 1-veined, acuminate; lower glumes 4-8 mm; upper glumes 6-11 mm; calluses 0.5-0.8 mm; lemmas 6-9 mm, slightly keeled, midveins scabrous, junction with the awns not evident; awns not disarticulating at maturity, flattened and straight to somewhat curved at the base, central rib flanked by equally wide pale wings; central awns 7-15(20) mm; lateral awns somewhat shorter, occasionally only 1-2 mm; anthers 3, 0.3-0.7 mm. |
unequal, 1-2-veined; lower glumes 4-10 mm; upper glumes 7-15 mm; calluses about 1 mm; lemmas 5-7 mm, purple or mottled, junction of the lemma and awns evident; awns twisted together basally into a 4-26 mm column, free portions 12-50 mm, those of the central and lateral awns similar in length, curved to arcuate basally, straight and divergent distally, disarticulating at the base of the column at maturity; anthers 3, about 2 mm long. |
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2n | = 22. |
= 22. |
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Aristida adscensionis |
Aristida californica |
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Distribution |
AZ; CA; CO; KS; MD; MO; NE; NM; NV; NY; OK; SC; TX; UT; HI; PR; Virgin Islands
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AZ; CA
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Discussion | Aristida adscensionis grows in waste ground, along roadsides, and on degraded rangelands and dry hillsides, often in sandy soils. It is associated with woodland, prairie, and desert shrub communities. Its range extends from the United States south through Mexico and Central America to South America. Because Aristida adscensionis is highly variable in height, panicle size, and awn development, several varieties have been described. None are recognized here because most of the variation appears to be environmentally induced. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The range of both varieties of Aristida californica extends from the southwestern United States into northwestern Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 330. | FNA vol. 25, p. 319. | ||||
Parent taxa | Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida | Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | A. interrupta, A. bromoides, A. adscensionis var. modesta | |||||
Name authority | L. | Thurb. | ||||
Web links |