Bouteloua trifida

Thurb. ex S. Watson
Common names: Red grama
Treatment appears in FNA Volume 25. Treatment on page 264.

Plants perennial; cespitose, older plants occasionally shortly rhizomatous. Culms 5-40 cm, slender, wiry, erect or slightly geniculate at the lower nodes; lower internodes glabrous, shorter than those above. Leaves mostly basal; sheaths glabrous, sometimes scabridulous, becoming flattened, persistent; ligules 0.2-0.5 mm, of hairs; blades 0.7-8 cm long, 0.5-1.5 (2) mm wide, scabridulous, margins often with papillose-based hairs basally. Panicles 3-9 cm, with 2-7 branches; branches 7-25 mm, persistent, spreading, ascending, or appressed, straight to slightly arcuate, with 8-24 (32) spikelets, axes terminating in a spikelet; disarticulation above the glumes. Spikelets appressed to pectinate, reddish-purple; with 1 bisexual floret and 1 rudimentary floret. Glumes bilobed; lower glumes 1.7-3.4 mm, slightly shorter than the upper glumes, veins excurrent to 0.6 mm; upper glumes 1.9-4 mm, glabrous or pubescent, hairs not papillose-based, veins excurrent to 1 mm; lower lemmas 1.2-2.2 mm, glabrous, sparsely appressed-pubescent along the veins or densely appressed-pubescent for much of their length and on the margins, trilobed, lobes veined, tapering into 3 awns, awns 2.2-6.6 mm, central awns not flanked by membranous lobes; anthers 0.2-0.4 mm, yellow; rachilla segments glabrous; upper florets glabrous, of 3 equal awns, awns 2-7 mm. Caryopses 0.8-1.5 mm long, 0.3-0.6 mm wide. 2n = 20.

Distribution

N.Mex., Tex., Utah, Calif., Ariz., Nev.

Discussion

Bouteloua trifida grows on dry open plains, shrubby hills, and rocky slopes, at 2200-2500 m. Its range extends from the southwestern United States to central Mexico. It is a drought-resistant species that is some¬times mistaken for Aristida because of its delicate, cespitose growth habit and purplish, 3-awned spikelets. Juvenile plants may also be confused with B. barbata but that species is annual, with the central awn flanked by two membranous lobes and the lowest paleas 4-lobed and 2-awned.

Selected References

None.

Key

1 Lower lemmas densely appressed pubescent; awns 2.2-4.5 mm long; anthers 0.2-0.3 mm long Bouteloua trifida var. burkii
1 Lower lemmas glabrous or sparsely appressed pubescent along both sides of the veins; awns (3.2)4-6.6 mm long; anthers 0.3-0.4 mm long Bouteloua trifida var. trifida

"decumbent" is not a number.

... more about "Bouteloua trifida"
1 +  and 3 +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
J.K. Wipff +
Thurb. ex S. Watson +
1 (?) +  and 3 (?) +
well-developed +
0.2 cm2 mm <br />0.002 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
not pseudopetiolate +
0.7 cm7 mm <br />0.007 m <br /> (8 cm80 mm <br />0.08 m <br />) +
pubescent +  and glabrous +
scabridulous +
usually linear +  and lanceolate occasionally ovate +
0.5mm;1.5mm +
subdigitate +  and digitate +
75 cm750 mm <br />0.75 m <br /> (?) +
straight +  and slightly arcuate +
persistent +
appressed;ascending;appressed;ascending;spreading +
spikelike +
not woody +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
triangular +  and dome--shaped +
sometimes longer +
membranous +
Red grama +
geniculate +
slender +
5 cm50 mm <br />0.05 m <br /> (40 cm400 mm <br />0.4 m <br />) +
not woody +
N.Mex. +, Tex. +, Utah +, Calif. +, Ariz. +  and Nev. +
not waisted +
capillary +
pistillate +  and staminate +
4-lobed +  and trilobed +
sometimes longer +
rudimentary +
round +  and compressed +
reduced +
shorter or longer +
subtending +
both +  and 1 +
acuminate +  and acute +
subequal +  and unequal +
not papillose-based +  and papillose-based +
uncinate +
paniculate +  and racemose +
hollow +  and solid +
not absent +
5-veined +, 7-13-veined +  and 1-3-veined +
sometimes longer +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
membranous +
tapering +
membranous +
inconspicuous +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.34 cm3.4 mm <br />0.0034 m <br />) +
appressed-pubescent +  and glabrous +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
appressed-pubescent +
concealed +  and prominent +
2 +  and 1 +
3 cm30 mm <br />0.03 m <br /> (9 cm90 mm <br />0.09 m <br />) +
dry +  and fleshy +
spikelike +
elongate +
flabellate +
persistent +
scabridulous +
flattened +
sessile +  and subsessile +
8 +  and 24 +
pectinate +
1 (?) +  and 3 (?) +
compound +  and simple +
2 (?) +  and 3 (?) +
Gramineae +
Bouteloua trifida +
Bouteloua subg. Chondrosum +
species +
membranous +
pubescent +  and glabrous +
0.19 cm1.9 mm <br />0.0019 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
7 +  and 13 +
extended +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
plant +  and cespitose +
aquatic +  and terrestrial +