Poa lettermanii |
Poa suksdorfii |
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Letterman bluegrass, Letterman's blue grass |
Suksdorf's bluegrass, western blue grass |
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Habit | Plants perennial; not glaucous; densely tufted, not stoloniferous, not rhizomatous. | Plants perennial; not glaucous; densely tufted, not stoloniferous, not rhizomatous. |
Culms | 1-12 cm, slender. |
7-25 cm. |
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. |
closed for 1/7-1/4(1/3) their length, terete; ligules of cauline leaves 1-3 mm, milky white, usually densely scabrous, sometimes smooth, ligules of the upper innovation leaves 0.5-2.5 mm; innovation blades adaxially scabrous, hispidulous, or puberulent on and between the veins, lacking papillae on the long cells (at 100x); cauline blades folded to involute, moderately thick, soft or moderately firm, apices narrowly prow-shaped, flag leaf blades 1-2 mm wide, adaxial surfaces with 5-9 well-spaced ribs. |
Basal branching | all or mainly intra-vaginal. |
all or mainly intravaginal. |
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. |
3-6 cm, erect, narrowly lanceoloid, contracted, moderately congested; nodes with 1-2 branches; branches to 1.5 cm, erect, slender, terete, sulcate or angled, smooth or the angles moderately 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. |
4.2-7 mm, laterally compressed, often strongly anthocyanic; florets 2-4; rachilla internodes 1-1.5 mm, smooth, sometimes sparsely hispidulous. |
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. |
lanceolate, distinctly keeled, keels smooth; lower glumes shorter than to equaling the lowest lemmas, 3-veined; upper glumes frequently exceeding the lowest lemmas, 3-5-veined, exceeded by the upper lemmas; calluses glabrous; lemmas 4.1-5.8 mm, narrowly lanceolate, distinctly keeled, thin, glabrous, apices acute; palea keels scabrous; anthers 0.8-1.2(1.7) mm, infrequently aborted late in development. |
2n | = 14. |
= unknown. |
Poa lettermanii |
Poa suksdorfii |
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Distribution |
CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
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OR; WA; BC
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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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa suksdorfii is a high alpine species of open rocky ground in the Pacific Northwest. It used to be interpreted (Hitchcock 1951) as including California populations that are now placed in Poa pringlei (p. 564) or P. keckii (see previous). Poa suksdorfii has narrow panicles like P. pringlei and P. curtifolia (p. 589). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 580. | FNA vol. 24, p. 584. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Abbreviatae | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Abbreviatae |
Sibling taxa | ||
Synonyms | P. mor.tevansi | |
Name authority | Vasey | (Beal) Vasey ex Piper |
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