Poa lettermanii

Vasey
Common names: Letterman's bluegrass
Endemic
Synonyms: Poa mor.tevansi
Treatment appears in FNA Volume 24. Treatment on page 580.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants perennial; not glaucous; densely tufted, not stoloniferous, not rhizomatous. Basal branching all or mainly intravaginal. Culms 1-12 cm, slender. Sheaths closed for 1/6 – 1/4 their length, terete; ligules 1-3 mm, milky white to hyaline, smooth; blades 0.5-2 mm wide, flat or folded, or slightly inrolled, thin, without papillae (at 100x), apices narrowly prow-shaped. Panicles 1-3 cm, erect, contracted, usually exserted from the sheaths; branches to 1.5 cm, erect to steeply ascending, slender, sulcate or angled, smooth or the angles sparsely scabrous; pedicels shorter than the spikelets. Spikelets 3-4 mm, laterally compressed, green or anthocyanic; florets 2-3; rachilla internodes shorter than 1 mm, smooth. Glumes usually equaling or exceeding the lowest lemmas, sometimes also equaling or exceeding the upper florets, lanceolate to broadly lanceolate, distinctly keeled, keels smooth; lower glumes 3-veined; calluses glabrous; lemmas 2.5-3 mm, lanceolate, distinctly keeled, thin, usually glabrous, keels and marginal veins rarely sparsely puberulent proximally, apices acute; palea keels scabrous; anthers 0.2-0.8 mm. 2n = 14.

Distribution

Colo., Wash., Utah, Alta., B.C., Oreg., Mont., Wyo., Idaho, Calif., Nev.

Discussion

Poa lettermanii grows on rocky slopes of the highest peaks and ridges in the alpine zone, from northern British Columbia to western Alberta and south to California and Colorado, usually in the shelter of rocks or on mesic to wet, frost-scarred slopes. It is one of only three known diploid Poa species native to the Western Hemisphere. Its glabrous calluses and lemmas usually distinguish it from P. abbreviata (p. 582); it also differs in having flat or folded leaf blades, and shorter spikelets with glumes that are longer than the adjacent florets. Poa montevansii E.H. Kelso is tentatively included here, although its slightly longer lemmas that slightly exceed the glumes suggest that it may represent rare, glabrous forms of P. abbreviata.

Selected References

None.

Lower Taxa

None.

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

... more about "Poa lettermanii"
membranous +  and scarious +
puberulent +, hispidulous +, hairy +  and glabrous +
1.8 cm18 mm <br />0.018 m <br /> (?) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
scarious-hyaline +
acute +  and prow--shaped +
Robert J. Soreng +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
keeled +  and rounded +
strigose +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
inrolled +, folded +  and flat +
firm +  and soft +
5 cm50 mm <br />0.05 m <br /> (?) +
erect;steeply ascending +
hispidulous +, glabrous +, smooth or +  and sparsely densely scabrous +
slender +
0 cm0 mm <br />0 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
compressed +  and terete +
Letterman's bluegrass +
unbranched +  and hollow +
ascending +  and erect +
slender +
1 cm10 mm <br />0.01 m <br /> (12 cm120 mm <br />0.12 m <br />) +
not woody +
Colo. +, Wash. +, Utah +, Alta. +, B.C. +, Oreg. +, Mont. +, Wyo. +, Idaho +, Calif. +  and Nev. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
2 +  and 3 +
compressed +
reduced +
1-3(5)-veined +
shorter or longer +
subtending +
keeled +, lanceolate +  and broadly lanceolate +
usually subequal +  and or slightly longer +
exceeding the upper florets +, equaling +  and exceeding the lowest lemmas +
distributed +
uncinate +
0.1 cm1 mm <br />0.001 m <br /> (?) +
0 +  and 1/6 +
Oval (?) +  and Round (?) +
milky white +  and slightly greenish +
softly puberulent +  and short-villous +
puberulent +
5(7-11)-veined +
keeled +  and lanceolate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
erose +  and entire +
milky white +  and hyaline +
ciliolate +  and smooth +
lacerate +, truncate +  and acuminate +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
inconspicuous +
lobed +  and lanceolate +
milky white +  and slightly greenish +
glabrous +, scabrous +  and smooth +
concealed +  and prominent +
0 +  and 5 +
2 +  and 1 +
well-developed +
2-keeled +
subequal +
spikelike +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
dry +  and fleshy +
hispidulous +  and glabrous +
anthocyanic +  and green +
many +, 1 +  and 100 +
compressed +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
Poa mor.tevansi +
Poa lettermanii +
Poa sect. Abbreviatae +
species +
membranous +
parallel +  and converging +
branching +, not rhizomatous +  and not stoloniferous +
aquatic +  and terrestrial +