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needle grama

Photo is of parent taxon

Arizona needle grama

Habit Plants annual; tufted.
Culms

4-60 cm, outer culms of a tuft decumbent, sometimes geniculate, branched at the lower nodes.

Spikelets

appressed.

Caryopses

2.5-3 mm.

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.

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.

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.

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.

2n

= 40.

Bouteloua aristidoides

Bouteloua aristidoides var. arizonica

Distribution
from FNA
AZ; CA; MD; NM; NV; TX; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; NM
[BONAP county map]
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.)

Key
1. Panicle branches with 2-5 spikelets, usually 5-16 mm to the base of the terminal spikelets, axes usually extending an additional 6-10 mm
var. aristidoides
1. Panicle branches with 6-10 spikelets, usually 15-35 mm to the base of the terminal spikelets, axes extending an additional 2-5(7) mm
var. arizonica
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
B. barbata, B. breviseta, B. chondrosoides, B. curtipendula, B. eludens, B. eriopoda, B. gracilis, B. hirsuta, B. kayi, B. parryi, B. radicosa, B. ramosa, B. repens, B. rigidiseta, B. simplex, B. trifida, B. uniflora, B. warnockii
B. aristidoides var. aristidoides
Subordinate taxa
B. aristidoides var. aristidoides, B. aristidoides var. arizonica
Name authority (Kunth) Griseb. M.E. Jones
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