Poa bulbosa |
Poa chambersii |
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bulbous blue grass |
Chambers' bluegrass |
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Habit | Plants perennial; densely tufted, not rhizomatous, not stoloniferous. | Plants perennial; loosely tufted or with solitary shoots, short-rhizomatous. | ||||
Culms | 15-60 cm, erect or spreading, bases bulbous. |
10-50 cm, erect or the bases decumbent, terete or weakly compressed; nodes terete, 0-1 exserted. |
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Sheaths | closed for about 1/4 their length, terete, lowest sheaths with swollen bases; ligules 1-3 mm, smooth or scabrous, apices obtuse to acute; blades 1-2.5 mm wide, flat, thin, lax, soon withering. |
closed for 1/3 – 7/8 their length, terete to slightly compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1.15)1.5-4.6(6.6) times blade lengths; collars smooth, glabrous; ligules 0.5-2(2.5) mm, smooth, truncate to obtuse; innovation blades similar to the cauline blades; cauline blades gradually reduced in length distally, 2-5 mm wide, flat or folded, smooth or the adaxial surfaces sparsely scabrous, primarily over the veins, apices broadly prow-shaped, flag leaf blades 0.7-6 cm. |
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Basal branching | intravaginal. |
all or mainly extravaginal. |
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Panicles | 3-12 cm, ovoid; nodes with 2-5 branches; branches ascending to spreading, terete, usually smooth or sparsely scabrous, infrequently moderately scabrous. |
2-9 cm, erect, lanceoloid to ovoid, tightly to loosely contracted, with 15-35 spikelets, proximal internodes shorter than 2 cm; nodes with 1-2 branches; branches 0.9-3.2 cm, erect to ascending or slightly spreading, terete, smooth or sparsely scabrous, with 1-4 spikelets. |
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Spikelets | 3-5 mm, laterally compressed, usually bulbiferous; florets 3-7, the basal floret, and sometimes additional florets, normal; rachilla internodes smooth, glabrous. |
6-12 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic; florets 2-7; rachilla internodes 0.8-1.5 mm, smooth or sparsely scabrous, glabrous. |
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Glumes | keeled, keels scabrous; lower glumes 3-veined; upper glumes shorter than or subequal to the lowest lemmas; calluses webbed or glabrous; lemmas 3-4 mm, lanceolate, keeled, glabrous or the keels and marginal veins short- to long-villous, intercostal regions glabrous or softly puberulent, apices acute; paleas scabrous, keels often softly puberulent at midlength; anthers 1.2-1.5 mm and functional, sometimes aborted late in development, sometimes not developed. |
3/5- 4/5 as long as the adjacent lemmas, distinctly keeled; lower glumes 3-veined; calluses of at least some proximal florets sparsely webbed, with 1-2 mm hairs, others glabrous, rarely all glabrous; lemmas 5-7 mm, lanceolate, 5-7-veined, distinctly keeled, smooth or sparsely finely scabrous, glabrous throughout or the keels and marginal veins sparsely softly puberulent over the proximal 1/4, lateral veins moderately prominent, intercostal regions glabrous, margins glabrous, apices acute; palea keels sparsely scabrous, intercostal regions glabrous; anthers vestigial (0.1-0.2 mm), aborted late in development, or 1.8-3.7 mm. |
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2n | = 14, 21, 28, 39, 42, 45. |
= unknown. |
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Poa bulbosa |
Poa chambersii |
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Distribution |
AR; AZ; CA; CO; CT; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MT; NC; ND; NE; NJ; NM; NV; NY; OH; OK; OR; PA; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY
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OR |
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Discussion | Poa bulbosa is a European species that is now established in the Flora region. In southern Europe and the Middle East, it is considered an important early spring forage. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa chambersii is known only from upland forest openings in the Cascades of western Oregon, where it is dioecious, and from high elevations on Steens Mountain in southeastern Oregon, where it is gynodioecious. It resembles P. rhizomata (see previous), but has more closed sheaths, shorter ligules, less pubescent or glabrous lemmas, and lacks a well-developed web. It approaches P. cusickii subsp. purpurascens (p. 562), but is rhizomatous and sexually reproducing. It differs from P. wheeleri (p. 546) in having glabrous sheaths and flat or folded, glabrous innovation blades. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24, p. 516. | FNA vol. 24, p. 548. | ||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Arenariae | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Poa | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | L. | Soreng | ||||
Web links |
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