Poa douglasii |
Poa bulbosa |
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bulbous bluegrass |
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Habit | Plants perennial but often appearing annual, producing bulblets, 15–60 cm tall, green; cespitose. | |
Culms | bulbous at the base; nodes terete. |
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Basal branching | intravaginal. |
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Leaves | sheaths closed about 25% of their length; basal sheaths swollen at the base; ligules 1–3 mm; blades flat, 1–2.5 mm wide; soon withering. |
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Inflorescences | ovoid, 3–12 cm; branches 2–5 per node, ascending to spreading. |
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Spikelets | 3–5 mm; florets 3–7, commonly all or all but the lowest producing bulblets, occasionally all producing seeds. |
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Glumes | keels scabrous; lower glumes 3-veined; upper glumes shorter than or subequal to lowest lemma. |
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Calluses | with cobwebby hairs or glabrous. |
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Lemmas | lanceolate, 3–4 mm, distinctly keeled, glabrous throughout, or keels and marginal veins shortto long-villous; area between veins glabrous or softly puberulent; tips acute. |
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Anthers | developed and 1.4–2 mm, or aborted late in development, or not developed. |
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2n | =21–42. |
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Poa douglasii |
Poa bulbosa |
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Distribution | ||
Discussion | Sunny to partly shady disturbed grasslands, shrub steppe, roadsides. 0–2300 m. All ecoregions except Est. CA, ID, NV, WA; throughout US; Mexico; temperate regions worldwide. Exotic. Poa bulbosa is usually recognized by the bulblets produced in the inflorescence. Occasional non-bulblet-producing plants can be recognized by their bulb-like shoot bases and the presence of bulb-bearing individuals nearby. Some botanists recognize two subspecies, P. b. ssp. bulbosa producing only normal caryopses and P. b. ssp. vivipara, producing bulblets. In Oregon, populations either are entirely viviparous or include both viviparous and seed-producing plants. |
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Source | Flora of Oregon, volume 1, page 454 Rob Soreng, Barbara Wilson, Richard Brainerd, Nick Otting |
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Sibling taxa | ||
Synonyms | Poa bulbosa ssp. bulbosa, Poa bulbosa ssp. vivipara | |
Web links |
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