sixweeks grama, more...
[Bouteloua arenosa Vasey, more]
Plants annual or short-lived perennials; tufted, sometimes with stolons.
Culms 1-75 cm, prostrate, decumbent, or erect, sometimes rooting at the
lower nodes; lower internodes glabrous. Leaves basal or cauline;
sheaths usually glabrous, except for tufts of long hairs on either side
of the collars; ligules 0.1-1 mm, membranous, ciliate; blades
0.5-10 cm long, 0.7-4 mm wide, adaxial surfaces usually sparsely pubescent with
a few papillose-based hairs basally. Panicles 0.7-25 cm, with (2)4-9(11)
branches; branches 10-30 mm, persistent, straight to arcuate, glabrous,
scabridulous, or with papillose-based hairs, with 20-55 spikelets, axes terminating
in a well-developed spikelet; disarticulation above the glumes. Spikelets
2.5-5 mm, pectinate, with 1 bisexual and 2 rudimentary florets. Glumes
unequal, glabrous, sometimes scabridulous, apices sometimes shortly bilobed,
acuminate or mucronate; lower glumes 0.7-1.5 mm; upper glumes
1.5-2.5 mm, glabrous, scabrous, or strigose, hairs not papillose-based; lowest
lemmas 1.7-4 mm, densely pilose, at least on the margins, 3-awned, awns
0.5-3 mm, central awns flanked by 2 membranous lobes; lowest paleas 1.5-4
mm, pubescent on the margins, 4-lobed, 2-awned, awns 1-2 mm; anthers
0.4-0.7 mm; rachilla internodes subtending second florets terminating
in a dense tuft of hairs; second florets rudimentary, 1.5-4 mm, 2-lobed,
lobes rounded, 3-awned, awns 0.5-4 mm; rachilla internodes subtending third
florets with glabrous or puberulent apices; third florets rudimentary,
flabellate, unawned. Caryopses to 1 mm. 2n = 20.
The range of Bouteloua barbata extends from the southwestern United States
to southern Mexico. It has occasionally been found as far north as southern
Montana, but it does not persist there and no voucher specimens exist. There
are three varieties of B. barbata. The two that grow in the Flora
region are often sympatric, but are usually easily distinguished in the field
in this region by their growth habit. According to Gould (1979), in the southern
portion of their range the differences between the two varieties are less evident,
particularly on herbarium specimens. The third variety, B. barbata var.
sonorae (Griffiths) Gould, is usually stoloniferous; it is known only
from the states of Sonora and Sinola, Mexico.
Bouteloua barbata is often confused with juvenile plants
of the perennial B. trifida, but in
B. barbata the central awn is flanked by two membranous lobes and the
lowest paleas are 4-lobed and 2-awned.
Dr. David Bogler, USDA NRCS PLANTS Database
Annuals, Terrestrial, not aquatic, Stolons or runners present, Stems trailing, spreading or prostrate, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence with 2 or more spikes, fascicles, glomerules, heads, or clusters per culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence with 2-10 branches, Inflorescence branches 1-sided, Inflorescence branches terminating in bristle or point, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent l emma, Glume equal to or longer than spikelet, Glumes 1 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 3 nerved, Lemma glabrous, Lemma body or surface hairy, Lemma apex dentate, 3-5 fid, Lemma teeth unequal. central tooth longer, Lemma distinctly awned, more than 2-3 mm, Lemma with 3 awns, Lemma awn less than 1 cm long, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.