Poa nemoralis |
Poa piperi |
|
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Eurasian woodland bluegrass, forest blue grass, interior bluegrass (ssp. interior), wood blue grass, woodland bluegrass, woods bluegrass (ssp. nemoralis) |
Piper's blue grass |
|
Habit | Plants perennial; green or glaucous; densely tufted, not stoloniferous, not rhizomatous. | Plants perennial; loosely tufted, rhizomatous. |
Culms | 30-80 cm, mostly erect, smooth below the panicles; nodes slightly compressed, 2-5 exserted, top node at 1/2 - 3/4 the culm length. |
20-55 cm, erect or the bases decumbent, terete or weakly compressed; nodes terete, 0-1 exserted. |
Sheaths | closed for 1/10 – 1/5 their length, terete, bases of basal sheaths glabrous, distal sheath lengths 0.45-1 (1.1) times blade lengths; ligules 0.2-0.8(1) mm, sparsely to densely scabrous, apices truncate, minutely ciliolate; blades 0.8-3 mm wide, mostly flat, appressed, abruptly ascending to spreading, straight or somewhat lax, apices narrowly prow-shaped. |
closed for 1/3-2/3 their length, terete, sparsely to moderately scabrous, glabrous or retrorsely hispidulous, bases of basal sheaths glabrous, distal sheath lengths 2.7-6.5(9.7) times blade lengths; collars of at least some leaves usually sparsely hispidulous; ligules 1-2 mm, scabrous, truncate to obtuse; innovation blades to 40 cm, adaxial surfaces moderately to densely scabrous or hispidulous on and between the veins; cauline blades steeply reduced in length distally, 1-3 mm wide, involute, moderately thick, soft, abaxial surfaces smooth, margins scabrous, apices narrowly prow-shaped, flag leaf blades 1-4.5 cm long. |
Basal branching | all or mostly extravaginal. |
extra- and intravaginal. |
Panicles | 7-16(20) cm, lengths usually 2.5-4 times widths at maturity, usually erect, lax in shade forms, narrowly lanceoloid to ovoid, slightly to moderately congested; nodes with 2-5 branches; branches ascending to widely spreading, fairly straight, slender to moderately stout, angled, angles moderately to densely scabrous. |
4-8 cm, erect to nodding, lanceoloid to ovoid, loosely contracted, sparse, with 18-60 spikelets; nodes with 1-2 branches; branches 3-8 cm, ascending, lax, terete or weakly angled, moderately and sometimes coarsely scabrous, with 3-8 spikelets. |
Spikelets | 3-8 mm, lengths 2.5-3.5 times widths, narrowly lanceolate to lanceolate, laterally compressed, usually not glaucous; florets (1)2-5; rachilla internodes usually shorter than 1 mm, smooth, muriculate, or scabrous, usually puberulent, infrequently hispidulous or glabrous. |
6-9(11) mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic; florets 2-5(7); rachilla internodes 1-2 mm, glabrous, scabrous, or sparsely to densely puberulent. |
Glumes | subulate to narrowly lanceolate, distinctly keeled, keels smooth or sparsely scabrous, apices sharply acute to acuminate; lower glumes 3-veined, long-tapered to a slender point, lengths 6.4-11 times widths; upper glumes shorter than or subequal to the lowest lemmas; calluses webbed, hairs sparse, often short; lemmas 2.4-4 mm, proximal lemma widths less than 1/5 times lengths, narrowly lanceolate to lanceolate, distinctly keeled, keels and marginal veins short-villous, lateral veins glabrous, obscure, intercostal regions smooth or muriculate, glabrous, margins glabrous, apices acute, usually partially bronze-colored; palea keels scabrous, intercostal regions glabrous; anthers 0.8-1.9 mm. |
subequal, distinctly keeled; lower glumes 3-veined; calluses diffusely webbed, hairs about 1/2 the lemma length; lemmas 4-6(7) mm, lanceolate, distinctly keeled, glabrous, smooth or sparsely to moderately finely scabrous, keels scabrous, lateral veins moderately prominent, margins glabrous, apices acute; palea keels scabrous, sometimes softly puberulent at midlength; anthers vestigial (0.1-0.2 mm) or 2-3 mm. |
2n | = 28, 35, 42, 48, 50, 56. |
= 28. |
Poa nemoralis |
Poa piperi |
|
Distribution |
AK; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OR; PA; RI; SD; TN; TX; UT; VA; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; ON; QC; SK; YT; Greenland
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CA; OR |
Discussion | Introduced from northern Eurasia, Poa nemoralis is established primarily at low elevations in deciduous and mixed conifer/deciduous forests. It is now common in southeastern Canada and the northeastern United States, and is spreading in the west. It can be distinguished from P. glauca (p. 576) and P. interior (see next) by its consistently short ligules, high top culm node, relatively long flag leaf blades, and narrow glumes and lemmas. It is usually hexaploid. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa piperi grows in forests openings on serpentine rocks in the Coast Ranges of southwestern Oregon and northwestern California. It used to be included in P. rhizomata (p. 546), from which it differs in its involute leaves and glabrous lemmas. It is dioecious. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 574. | FNA vol. 24. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Stenopoa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Madropoa |
Sibling taxa | ||
Name authority | L. | Hitchc. |
Web links |
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