Poa lettermanii |
Poa ammophila |
|
---|---|---|
Letterman bluegrass, Letterman's blue grass |
bluegrass, sand bluegrass |
|
Habit | Plants perennial; not glaucous; densely tufted, not stoloniferous, not rhizomatous. | Plants perennial; glaucous; densely tufted, not stoloniferous, not rhizomatous. |
Culms | 1-12 cm, slender. |
10-30 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 – 1/6 their length, terete, bases of basal sheaths glabrous; ligules 1.5-3 mm; innovation blades similar to the cauline blades; cauline blades 1-3 mm wide, involute, moderately thick, soft, abaxial surfaces smooth, adaxial surfaces smooth or sparsely scabrous, apices narrowly prow-shaped. |
Basal branching | all or mainly intra-vaginal. |
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, congested or moderately congested; nodes with (1)2(3) branches; branches 1-3(4) cm, erect, terete, smooth or sparsely scabrous. |
Spikelets | 3-4 mm, laterally compressed, green or anthocyanic; florets 2-3; rachilla internodes shorter than 1 mm, smooth. |
5-7 mm, lengths to 3.5 times widths, broadly lanceolate, weakly laterally compressed, fairly drab; florets 2-4; rachilla internodes usually 1-1.3 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. |
lanceolate, distinctly keeled, keels smooth; lower glumes 3-veined; calluses glabrous; lemmas 3-4.6 mm, lanceolate, distinctly to weakly keeled, evenly and densely strigulose over the proximal 1/3-1/2, hairs mostly about 0.1 mm, some keel hairs to 0.2(0.3) mm, lateral veins obscure, margins broadly scarious, glabrous, apices acute; palea keels scabrous, softly puberulent at midlength, intercostal regions softly puberulent; anthers 1.5-1.8 mm. |
2n | = 14. |
= unknown. |
Poa lettermanii |
Poa ammophila |
|
Distribution |
CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
|
NT; YT |
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 ammophila is endemic to the Mackenzie River Delta region, Northwest Territories. It grows primarily north of treeline and, as its name indicates, usually on sandy soils. Its close relative, P. hartzii (see previous), also reaches the continental coastline in this region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 580. | FNA vol. 24, p. 592. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Abbreviatae | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Secundae > subsect. Secundae |
Sibling taxa | ||
Synonyms | P. mor.tevansi | P. hartzii subsp. ammophila |
Name authority | Vasey | A.E. Porsild |
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