Bouteloua aristidoides |
Bouteloua simplex |
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needle grama |
mat grama, Matted grama |
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Habit | Plants annual; tufted. | Plants annual. | ||||
Culms | 4-60 cm, outer culms of a tuft decumbent, sometimes geniculate, branched at the lower nodes. |
3-35 cm, usually decumbent, occasionally erect, rarely branching; internodes glabrous. |
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Sheaths | smooth, deeply striate; ligules 0.1-0.2 mm, of short hairs, sometimes with a few papillose-based hairs on either side; blades 2-8 cm long, 0.5-1.5 mm wide, flat to involute, adaxial surfaces mostly glabrous, often pilose basally. |
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Panicles | 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. |
usually with only 1 branch (terminating the culm), or with 2-4 branches and subdigitate; branches 10-25(40) mm, persistent, straight, arcuate, or circular, with 30-80 spikelets, axes terminating in a reduced spikelet; disarticulation above the glumes. |
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Spikelets | appressed. |
pectinate, with 1 bisexual floret and 1-2 rudimentary florets. |
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Glumes | glabrous, sometimes scabrous distally, acute or acuminate; lower glumes 1.5-2.5 mm; upper glumes 3.5-5 mm; lowest lemmas 2.5-3.5 mm, pilose over the veins, 3-awned, awns stout and flattened, central awns 1-2 mm, flanked by 2 membranous lobes, lateral awns shorter than the central awns; lowest paleas obovate, unawned; rachilla segments subtending second florets with densely pubescent apices; second florets reduced to an awn column with 3 awns of 5-6 mm; third florets, if present, flabellate scales. |
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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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2n | = 40. |
= 20. |
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Bouteloua aristidoides |
Bouteloua simplex |
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Distribution |
AZ; CA; MD; NM; NV; TX; UT
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AZ; CO; KS; ME; NE; NM; TX; UT; WY
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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 simplex grows on rocky, open slopes in grassy and open shrub vegetation at 1200-2500 m. Its native range extends from the southwestern United States through Mexico and Central America to western South America. It is adventive in Maine, where it has been grows in disturbed places, but it is not common there. (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. 265. | ||||
Parent taxa | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Bouteloua > subg. Bouteloua | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Bouteloua > subg. Chondrosum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Chondrosum prostratum, B. procumbens | |||||
Name authority | (Kunth) Griseb. | Lag. | ||||
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