Poa bigelovii

Vasey & Scribn.
Common names: Bigelow’s bluegrass
Treatment appears in FNA Volume 24. Treatment on page 536.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants usually annual, rarely longer-lived; densely tufted, tuft bases narrow, usually without sterile shoots, not stolonigerous, not rhizomatous. Basal branching intravaginal. Culms (2) 5-60 (70) cm tall, 0.3-1 mm thick, usually erect, bases rarely geniculate; nodes terete, usually 1 exserted. Sheaths closed for 1/4 - 1/2 their length, usually compressed and keeled, smooth or the keels scabrous; ligules 2-6 mm, smooth or scabrous, usually decurrent, obtuse to acute; blades 1.5-5 mm wide, flat, thin, soft, finely scabrous, apices broadly prow-shaped, cauline blades (1) 4-15 cm, flag leaf-blades usually 1-4 cm. Panicles (1) 5-15 cm, erect, cylindrical, contracted, sometimes interrupted, congested, with 2-3 (5) branches per node; branches erect or steeply ascending, smooth or sparsely to densely scabrous. Spikelets 4-7 mm, laterally compressed; florets 3-7; rachilla internodes to 1 mm, smooth, glabrous. Glumes subequal, distinctly keeled, keels and sometimes the lateral-veins scabrous; lower glumes 1 (3) -veined; upper glumes shorter than or subequal to the lowest lemmas; calluses webbed; lemmas 2.6-4.2 mm, lanceolate, distinctly keeled, smooth, keels, marginal veins, and sometimes the lateral-veins short to long-villous, keels hairy to near the apices, marginal veins to 2/3 their length, lateral-veins obscure to moderately prominent, intercostal regions glabrous or softly puberulent, upper margins white, apices acute; palea keels softly puberulent to short-villous at midlength, scabrous near the apices, intercostal regions usually softly puberulent; anthers 1-3, 0.2-1 mm. 2n = 28, 28+1.

Distribution

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

Discussion

Poa bigelovii grows in arid upland regions, particularly on shady, rocky slopes of the southwestern United States and northern Mexico. Plants from southeastern Arizona eastwards are usually glabrous between the lemma veins, whereas more western plants are usually puberulent between the lemma veins. Plants with 1 or 2 small anthers are found in the eastern portion of the species' range; they differ from P. chapmaniana (p. 534) in their persistently contracted panicles and broader leaf blades.

Selected References

None.

Lower Taxa

None.

No values specified.No values specified."decumbent" is not a number.

... more about "Poa bigelovii"
membranous +  and scarious +
puberulent +, hispidulous +, hairy +  and glabrous +
1.8 cm18 mm <br />0.018 m <br /> (?) +
1.5mm +  and 3mm +
3 +  and 1 +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
scarious-hyaline +
midlength +
puberulent +
acute +  and prow--shaped +
Robert J. Soreng +
Vasey & Scribn. +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
keeled +  and rounded +
strigose +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
geniculate +
swelling +
not evident +
involute +, folded +  and flat +
ascending;erect +
hispidulous +, glabrous +, smooth or +  and sparsely densely scabrous +
angled +  and terete +
0.5 cm5 mm <br />0.005 m <br /> (20 cm200 mm <br />0.2 m <br />) +
compressed +  and terete +
folded +  and flat +
4 cm40 mm <br />0.04 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Bigelow’s bluegrass +
unbranched +  and hollow +
5 cm50 mm <br />0.05 m <br /> (60 cm600 mm <br />0.6 m <br />) +
compressed +  and terete +
2 cm20 mm <br />0.02 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
not woody +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Okla. +, N.Mex. +, Tex. +, Utah +, Calif. +, Colo. +, Ariz. +  and Nev. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
3 +  and 7 +
compressed +
reduced +
1-3(5)-veined +
shorter or longer +
subtending +
subequal +
distributed +
uncinate +
0.1 cm1 mm <br />0.001 m <br /> (?) +
0 +  and 1/6 +
Oval (?) +  and Round (?) +
milky white +  and slightly greenish +
puberulent +  and glabrous +
obscure +  and moderately prominent +
5(7-11)-veined +
hairy +  and glabrous +
keeled +  and lanceolate +
0.26 cm2.6 mm <br />0.0026 m <br /> (0.42 cm4.2 mm <br />0.0042 m <br />) +
membranous +
erose +  and entire +
milky white +
ciliolate +  and smooth +
obtuse +  and acute +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
membranous +
inconspicuous +
lobed +  and lanceolate +
milky white +
glabrous +, scabrous +  and smooth +
concealed +  and prominent +
2 +  and 1 +
well-developed +
2-keeled +
subequal +
1 cm10 mm <br />0.01 m <br /> (?) +
cylindrical +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
dry +  and fleshy +
keeled +  and compressed +
branching +, rhizomatous +  and stoloniferous +
many +, 1 +  and 100 +
compressed +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Poa bigelovii +
Poa sect. Homalopoa +
species +
membranous +
parallel +  and converging +
aquatic +  and terrestrial +