Poa cusickii |
Poa hartzii |
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Cusick's bluegrass |
Hartz's bluegrass |
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Habit | Plants perennial; usually densely tufted, rarely moderately densely tufted, usually neither rhizomatous nor stoloniferous, infrequently short-rhizomatous or stoloniferous, rarely with distinct rhizomes. | Plants perennial; not glaucous; densely to loosely tufted, not rhizomatous,occasionally weakly stoloniferous. | ||||||||||||||||||||
Culms | 10-60(70) cm tall, 0.5-1.8 mm thick, erect or the bases decumbent, terete or weakly compressed; nodes terete, 0-2 exserted. |
10-33(45) cm, usually decumbent, terete; nodes terete, 0(1) exserted. |
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Sheaths | closed for 1/4-3/4 their length, terete, smooth or scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.6-10 times blade lengths; collars smooth or scabrous, glabrous; ligules of cauline leaves 1-3(6) mm, smooth or scabrous, truncate to acute, ligules of the innovation leaves 0.2-0.5(2.5) mm, scabrous, usually truncate; innovation blades sometimes distinctly different from the cauline blades, 0.5-2 mm wide, involute, moderately thick, moderately firm, adaxial surfaces usually densely scabrous or hispidulous to softly puberulent, infrequently nearly smooth and glabrous; cauline blades subequal or the midcauline blades longest or the blades gradually reduced in length distally, 0.5-3 mm wide, flat, folded, or involute, usually thin, usually withering, abaxial surfaces smooth or scabrous, apices narrowly to broadly prow-shaped, flag leaf blades 0.5-5(6) cm. |
closed for 1/7 – 1/5(1/3) their length, terete, usually lustrous, bases of basal sheaths glabrous; ligules (1.5)2-7 mm, smooth or sparsely scabrous, margins usually decurrent, apices obtuse to acuminate; innovation blades similar in texture and shape to those of the culms; cauline blades 2-9 cm, gradually increasing or decreasing in length upwards, 1.5-3 mm wide, folded to involute, moderately thick, soft, abaxial surfaces smooth, adaxial surfaces smooth or somewhat scabrous, usually glabrous, infrequently sparsely hispidulous, apices narrowly prow-shaped. |
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Basal branching | intravaginal or intra- and extravaginal. |
extra- and intravaginal. |
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Panicles | 2-10(12) cm, usually erect, contracted or loosely contracted, narrowly lanceoloid to ovoid, congested or moderately congested, with 10-100 spikelets and 1-3(5) branches per node; branches 0.5-4(5) cm, erect or steeply ascending, fairly straight, slender to stout, terete to angled, smooth or scabrous, with 1-15 spikelets. |
2.5-6(12) cm, erect, narrowly lanceolate, contracted or narrowly ovate in some bulbiferous plants, moderately congested, with 7-40 spikelets; nodes with (1)2(4) branches; branches 1-3 cm, erect to ascending, straight, sulcate, smooth or sparsely to moderately scabrous, with 1-10 spikelets in the distal 1/3 – 2/3. |
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Spikelets | (3)4-10 mm, lengths to 3 times widths, broadly lanceolate to narrowly ovate, laterally compressed, not sexually dimorphic; florets 2-6; rachilla internodes 0.5-1.2 mm, smooth or scabrous. |
4.8-7.4 mm, lengths 3.5-4 times widths, lanceolate, weakly laterally compressed, sometimes bulbiferous, lustrous; florets (2)3-5(6), normal or bulb-forming; rachilla internodes 0.8-2 mm, smooth, sometimes sparsely hispidulous. |
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Glumes | lanceolate, distinctly keeled; lower glumes 3-veined, distinctly shorter than the lowest lemmas; calluses glabrous or diffusely webbed, hairs less than 1/4 the lemma length; lemmas (3)4-7 mm, lanceolate to broadly lanceolate, distinctly keeled, membranous to thinly membranous, smooth or sparsely to densely scabrous, glabrous or the keels and/or marginal veins puberulent proximally, lateral veins obscure to prominent, margins glabrous, apices acute; palea keels scabrous, intercostal regions glabrous; anthers vestigial (0.1-0.2 mm), aborted late in development, or 2-3.5 mm. |
mostly broadly scarious, somewhat lustrous, keels indistinct, smooth or sparsely scabrous distally; lower glumes 3-veined; upper glumes frequently exceeding the lowest lemmas; calluses glabrous or with a crown of hairs, hairs to 2 mm; lemmas (3.3)3.5-7 mm, lanceolate, usually weakly keeled, more or less evenly and somewhat loosely to densely hairy over the proximal 1/3-1/2, hairs usually longer than 0.5 mm, sparsely scabrous in the middle 1/3, smooth distally, lateral veins obscure, margins weakly inrolled, broadly scarious, glabrous, apices long-scarious, acute to shortly obtuse, often erose, often bronze-colored below the apices; palea keels sparsely scabrous, softly puberulent at midlength, intercostal regions softly puberulent; anthers usually all aborted late in development and 0.8-1.8 mm, infrequently well developed and 2-2.8 mm. |
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2n | = 28, 28+11, 56, 56+11, 59, ca. 70. |
= 63, 70. |
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Poa cusickii |
Poa hartzii |
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Distribution |
CA; CO; ID; MT; ND; NV; OR; UT; WA; WY; AB; BC; MB; SK; YT
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AK; NT; NU; QC; Greenland |
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Discussion | Poa cusickii grows in rich meadows in sagebrush scrub to rocky alpine slopes, from the southwestern Yukon Territory to Manitoba and North Dakota, south to central California and eastern Colorado. It is gynodioecious or dioecious. Sexually reproducing plants of Poa cusickii subspp. cusickii and pallida grow in different geographic areas, but pistillate plants of these two subspecies have overlapping ranges. Only pistillate plants are known in Poa cusickii subspp. epilis and purpurascens. All the alpine plants studied were pistillate. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa hartzii grows only in the high arctic. It generally grows on open ground, on sandy or clayey soils, or on slumping slopes of old marine terraces. It carries two chloroplast genomes within its populations; one of these links it to P. secunda (p. 586) and P. ammophila (see next), the other to P. glauca (p. 576). Morphologically, it is closest to P. secunda and P. ammophila. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24, p. 559. | FNA vol. 24, p. 589. | ||||||||||||||||||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Epiles | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Secundae > subsect. Secundae | ||||||||||||||||||||
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Name authority | Vasey | Gand. | ||||||||||||||||||||
Web links |
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