Poa bolanderi |
Poa compressa |
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Bolander's blue grass |
Canada blue grass, Canadian blue grass, flat-stem blue grass |
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Habit | Plants usually annual, rarely longer-lived; often glaucous; densely tufted, tuft bases narrow, sterile shoots few, not stoloniferous, not rhizomatous. | Plants perennial; usually with solitary shoots, sometimes loosely tufted, extensively rhizomatous. |
Culms | 20-60(70) cm, erect or geniculate at the base; nodes terete, usually 1-3 exserted. |
15-60 cm, wiry, bases usually geniculate, strongly compressed; nodes strongly compressed, some proximal nodes usually exserted. |
Sheaths | 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. |
closed for 1/10 – 1/5 their length, distinctly compressed, bases of basal sheaths glabrous; ligules 1-3 mm, moderately to densely scabrous, ciliolate, apices obtuse; blades 1.5-4 mm wide, flat, cauline blades subequal. |
Basal branching | both intra- and extravaginal. |
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Panicles | (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. |
2-10 cm, generally 1/6 - 1/3 as wide as long, erect, linear, lanceoloid to ovoid, often interrupted, sparse to congested, with 15-80 spikelets and mostly with 1-3 branches per node; branches 0.5-3 cm, erect to ascending, or infrequently spreading, angles densely scabrous, at least in part, with 1-15 spikelets. |
Spikelets | (3)4-7 mm, laterally compressed; florets 2-3(4); rachilla internodes usually 1-1.2+ mm, smooth or sparsely scabrous, glabrous. |
(2.3)3.5-7 mm, laterally compressed; florets 3-7; rachilla internodes usually shorter than 1 mm, smooth to muriculate. |
Glumes | 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. |
distinctly keeled; lower glumes 3-veined; calluses usually webbed, sometimes glabrous; lemmas 2.3-3.5 mm, lanceolate, distinctly keeled, keels and marginal veins short-villous, intercostal regions glabrous, lateral veins obscure, margins glabrous, apices acute; paleas scabrous over the keels; anthers 1.3-1.8 mm. |
2n | = 28. |
= 35, 42, 49, 50, 56, 84. |
Poa bolanderi |
Poa compressa |
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Distribution |
CA; ID; NV; OR; UT; WA; BC
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT
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Discussion | 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.) |
Poa compressa is common in much of the Flora region. It is sometimes considered to be native, but this seems doubtful. It is rare and thought to be introduced in Siberia and only local in the Russian Far East, but is common in Europe. In the Flora region, it is often seeded for soil stabilization, and has frequently escaped. It grows mainly in riparian areas, wet meadows, and disturbed ground. Its distinctly compressed nodes and culms, exserted lower culm nodes, rhizomatous growth habit, and scabrous panicle branches make it easily identifiable. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 533. | FNA vol. 24, p. 579. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Tichopoa |
Sibling taxa | ||
Synonyms | P. howellii var. chandleri | |
Name authority | Vasey | L. |
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