Poa autumnalis |
Poa bolanderi |
|
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autumn bluegrass |
Bolander's blue grass |
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Habit | Plants perennial; not rhizomatous, not stoloniferous, loosely tufted. | Plants usually annual, rarely longer-lived; often glaucous; densely tufted, tuft bases narrow, sterile shoots few, not stoloniferous, not rhizomatous. |
Culms | 23-86 cm tall, 0.8-1.8 mm thick, bases often decumbent. |
20-60(70) cm, erect or geniculate at the base; nodes terete, usually 1-3 exserted. |
Sheaths | closed for 1/3 – 1/2 their length; ligules 0.2-1.9(2.5) mm, smooth or obtuse; blades (0.5)1-4 mm wide, flat or folded, thin. |
closed for 1/2-1/4 their length, usually compressed and keeled, usually smooth, infrequently scabrous; ligules 2.5-7 mm, smooth or scabrous, usually decurrent, obtuse to acute; blades 1.5-5 mm wide, usually flat, rarely folded, lax, soft, smooth or sparsely scabrous, margins scabrous, apices broadly prow-shaped, cauline blades 3-15 cm, flag leaf blades 1-4 cm. |
Basal branching | mainly pseudointravaginal. |
both intra- and extravaginal. |
Panicles | (5)8-20 cm, erect or lax, broadly pyramidal at maturity, open, sparse, lower axils sometimes sparsely pubescent; nodes with 1-2(4) branches; branches 5-12 cm, spreading to reflexed, straight, angled, angles scabrous, with 3-8 spikelets in the distal 1/4-1/3. |
(5)10-15(25) cm long, 1/4-1/2 the plant height, usually erect, infrequently slightly nodding, usually eventually open, sometimes interrupted, sparse, with 1-3(5) branches per node; branches initially erect and straight, usually some eventually spreading or reflexed, smooth or sparsely to moderately scabrous. |
Spikelets | 3-8.2 mm, laterally compressed; florets 2-4(6); rachilla internodes smooth, sparsely softly puberulent. |
(3)4-7 mm, laterally compressed; florets 2-3(4); rachilla internodes usually 1-1.2+ mm, smooth or sparsely scabrous, glabrous. |
Glumes | distinctly shorter than the adjacent lemmas, distinctly keeled, keels scabrous; lower glumes subulate to lanceolate, (1)3-veined; upper glumes lanceolate to broadly lanceolate; calluses usually glabrous, rarely sparsely and shortly webbed; lemmas (2.8)3-4.6 mm, lanceolate, distinctly keeled, keels and marginal veins short- to long-villous, hairs extending up 3/4 of the keel, lateral veins prominent, intercostal regions softly puberulent, smooth, apices obtuse, blunt; palea keels softly puberulent to short-villous for much of their length, apices scabrous; anthers 1-1.4(2.6) mm. |
unequal, distinctly shorter than the adjacent lemmas, distinctly keeled, keels smooth or sparsely scabrous; lower glumes 1-3-veined, 1/2 - 2/3 the length of the upper glume, 1/2 - 2/3 the length of the lowest lemmas; upper glumes shorter than or subequal to the lowest lemmas; calluses of some or all florets sparsely webbed; lemmas 2.5-4 mm, lanceolate to narrowly lanceolate, distinctly keeled, smooth or scabrous throughout, glabrous, lateral veins obscure to moderately prominent, apices narrowly acute, usually anthocyanic near the tip; palea keels sparsely scabrous; anthers 3, 0.5-1(1.8) mm. |
2n | = 28. |
= 28. |
Poa autumnalis |
Poa bolanderi |
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Distribution |
AL; AR; DC; DE; FL; GA; IL; IN; KY; LA; MD; MI; MS; NC; NJ; OK; PA; SC; TN; TX; VA; NU; QC; Greenland
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CA; ID; NV; OR; UT; WA; BC
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Discussion | Poa autumnalis grows primarily in the southeastern United States, being found in forests of the eastern and western Appalachian piedmont and coastal plain. It is readily distinguished from other perennial species of the eastern United States by its combination of glabrous calluses and pubescent palea keels. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa bolanderi grows mainly in pine to fir forest openings of mountain slopes in the western United States, from Washington to California and Utah. It differs from P. howellii (see below) in having smooth to scabrous, rather than puberulent, lemmas; it also grows at higher elevations, mostly at 1500-3000 m. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 514. | FNA vol. 24, p. 533. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Sylvestres | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa |
Sibling taxa | ||
Synonyms | P. howellii var. chandleri | |
Name authority | Muhl. ex Elliott | Vasey |
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