Poa arida |
Poa leibergii |
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Leiberg's bluegrass |
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Habit | Plants perennial, gynodioecious, 5–35 cm tall; densely cespitose. | |
Culms | 0.5–0.7 mm thick; nodes 0–1 exserted. |
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Basal branching | intravaginal. |
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Leaves | sheaths closed 40–60% of their length, bases of basal sheaths glabrous; collars smooth, glabrous; ligules (1)2–4 mm long; hyaline; smooth, sterile shoot ligules like those of the culm leaves, blades of tillers with lower surfaces smooth or sparsely scabrous; cauline blades flat, folded or involute, 0.5–1(1.5)mm wide, usually soon withering; smooth or sparsely scabrous. |
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Inflorescences | erect to lax, lanceoloid to ovoid or pyramidal, contracted to open, 1–5(8) cm; spikelets (1)6–17(22); branches erect to spreading; slender, 1–4 cm, 1–2 per node, with 1–2(3) spikelets. |
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Spikelets | broadly lanceolate to broadly ovate; to 3 times as long as wide, 4–8 mm; florets 2–3; rachilla internodes glabrous. |
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Glumes | thin; somewhat shiny; lower glumes 3-veined, distinctly shorter than the lowest lemma. |
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Calluses | glabrous. |
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Lemmas | lanceolate, 3.5–7 mm, distinctly keeled, thinly membranous; smooth or scabrous, glabrous; tips acute to truncate and erose. |
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Anthers | vestigial and 0.1–0.2 mm, or 1.3–3 mm. |
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Poa arida |
Poa leibergii |
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Distribution | ||
Discussion | Wet rock ledges, vernal pools, edges of wet meadows, in sagebrush steppe to alpine habitats. 50–2900m. BW, Col, ECas, Lava. ID, NV, WA. Native. Poa leibergii is a cespitose upland species, lacking cobwebby callus hairs. It is most likely to be confused with P. cusickii ssp. cusickii, which has shorter ligules on the leaves of vegetative shoots and more condensed panicles with more spikelets. |
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Source | Flora of Oregon, volume 1, page 458 Rob Soreng, Barbara Wilson, Richard Brainerd, Nick Otting |
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Sibling taxa | ||
Synonyms | Poa vaseyochloa | |
Web links |