Bouteloua aristidoides |
Bouteloua aristidoides var. arizonica |
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needle grama |
Arizona needle grama |
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Habit | Plants annual; tufted. | |||||
Culms | 4-60 cm, outer culms of a tuft decumbent, sometimes geniculate, branched at the lower nodes. |
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Spikelets | appressed. |
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Caryopses | 2.5-3 mm. |
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Ligules | 0.2-0.5 mm, membranous, lacerate or ciliate; blades 2-5(9) cm long, 0.7-2 mm wide, flat or folded, adaxial surfaces sometimes with papillose-based hairs, margins usually with papillose-based hairs near the ligules. |
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Proximal | spikelet on each branch with 1 floret; lower glumes 1.5-3.5 mm, glabrous, narrow to subulate; upper glumes 5.5-6.2 mm, densely pubescent, at least on the basal 1/2; lemmas 5.8-6 mm, acuminate, unawned; lowest paleas almost as long as the lemmas, bifid, glabrous; rachillas prolonged beyond the florets for about 0.5 mm. |
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Distal | spikelets with 1 bisexual and 1 rudimentary floret, glumes unequal, glabrous, minutely scabrous on the keels; narrowly acute or acuminate; lower glumes 1.5-2 mm; upper glumes 5-6 mm, glabrous or sparsely pubescent basally, often divergent; lowest lemmas 6-8 mm, veins pubescent, lateral veins excurrent as short (to 1 mm) awns, acuminate, midvein extended into a setaceous tip or a short awn; lowest paleas 5-7 mm, bifid, veins often excurrent as short awns; anthers about 2.5 mm, yellow or yellow and red; distal florets reduced to a pubescent, 3-awned, awn column, awns 2-7 mm, exserted. |
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Panicle(s) | 2.5-10.5 cm, with (1)4-15 branches; branches 5-45 mm, deciduous, densely pubescent (at least basally), with 2-10 spikelets per branch, axes extending 2-10 mm beyond the base of the terminal spikelets, apices entire; disarticulation at the base of the branches, the break forming a sharp tip. |
branches 15-35 mm to the base of the terminal spikelets and extending an additional 1.5-5(7) mm, with 6-10 spikelets. |
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2n | = 40. |
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Bouteloua aristidoides |
Bouteloua aristidoides var. arizonica |
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Distribution |
AZ; CA; MD; NM; NV; TX; UT
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AZ; NM |
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Discussion | There are two varieties, both of which grow in the Flora region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Bouteloua aristidoides var. arizonica grows in the same kind of habitats as var. aristidoides, but only from 500-800 m. It has a more restricted range than B. aristidoides var. aristidoides (which extends into northern Mexico), being known only from New Mexico, Arizona, and Chihuahua, Mexico. In its extreme form, var. arizonica is very different from var. aristidoides, but the two varieties do intergrade. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 255. | FNA vol. 25, p. 257. | ||||
Parent taxa | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Bouteloua > subg. Bouteloua | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Bouteloua > subg. Bouteloua > Bouteloua aristidoides | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | (Kunth) Griseb. | M.E. Jones | ||||
Web links |