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Eurasian woodland bluegrass, forest blue grass, interior bluegrass (ssp. interior), wood blue grass, woodland bluegrass, woods bluegrass (ssp. nemoralis)

Bigelow bluegrass, Bigelow's blue grass

Habit Plants perennial; green or glaucous; densely tufted, not stoloniferous, not rhizomatous. Plants usually annual, rarely longer-lived; densely tufted, tuft bases narrow, usually without sterile shoots, not stolonigerous, not 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.

(2)5-60(70) cm tall, 0.3-1 mm thick, usually erect, bases rarely geniculate;

nodes terete, usually 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 1/4 - 1/2 their length, usually compressed and keeled, smooth or the keels scabrous;

ligules 2-6 mm, smooth or scabrous, usually decurrent, obtuse to acute;

blades 1.5-5 mm wide, flat, thin, soft, finely scabrous, apices broadly prow-shaped, cauline blades (1)4-15 cm, flag leaf blades usually 1-4 cm.

Basal branching

all or mostly extravaginal.

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.

(1)5-15 cm, erect, cylindrical, contracted, sometimes interrupted, congested, with 2-3(5) branches per node;

branches erect or steeply ascending, smooth or sparsely to densely scabrous.

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.

4-7 mm, laterally compressed;

florets 3-7;

rachilla internodes to 1 mm, smooth, glabrous.

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, keels and sometimes the lateral veins scabrous;

lower glumes 1(3)-veined;

upper glumes shorter than or subequal to the lowest lemmas;

calluses webbed;

lemmas 2.6-4.2 mm, lanceolate, distinctly keeled, smooth, keels, marginal veins, and sometimes the lateral veins short- to long-villous, keels hairy to near the apices, marginal veins to 2/3 their length, lateral veins obscure to moderately prominent, intercostal regions glabrous or softly puberulent, upper margins white, apices acute;

palea keels softly puberulent to short-villous at midlength, scabrous near the apices, intercostal regions usually softly puberulent;

anthers 1-3, 0.2-1 mm.

2n

= 28, 35, 42, 48, 50, 56.

= 28, 28+1.

Poa nemoralis

Poa bigelovii

Distribution
from FNA
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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[BONAP county map]
from FNA
AZ; CA; CO; NM; NV; OK; TX; UT
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[BONAP county map]
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 bigelovii grows in arid upland regions, particularly on shady, rocky slopes of the southwestern United States and northern Mexico. Plants from southeastern Arizona eastwards are usually glabrous between the lemma veins, whereas more western plants are usually puberulent between the lemma veins. Plants with 1 or 2 small anthers are found in the eastern portion of the species' range; they differ from P. chapmaniana (p. 534) in their persistently contracted panicles and broader leaf blades.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 574. FNA vol. 24, p. 536.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Stenopoa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa
Sibling taxa
P. abbreviata, P. alpina, P. alsodes, P. ammophila, P. annua, P. arachnifera, P. arctica, P. arida, P. arnowiae, P. atropurpurea, P. autumnalis, P. bigelovii, P. bolanderi, P. bulbosa, P. chaixii, P. chambersii, P. chapmaniana, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. cuspidata, P. diaboli, P. douglasii, P. eminens, P. fendleriana, P. glauca, P. hartzii, P. howellii, P. infirma, P. interior, P. keckii, P. kelloggii, P. laxa, P. laxa × glauca, P. laxiflora, P. leibergii, P. leptocoma, P. lettermanii, P. macrantha, P. macrocalyx, P. marcida, P. napensis, P. nervosa, P. occidentalis, P. paludigena, P. palustris, P. paucispicula, P. piperi, P. porsildii, P. pratensis, P. pringlei, P. pseudoabbreviata, P. reflexa, P. rhizomata, P. saltuensis, P. secunda, P. sierrae, P. stebbinsii, P. stenantha, P. strictiramea, P. sublanata, P. suksdorfii, P. supina, P. sylvestris, P. tenerrima, P. tracyi, P. trivialis, P. unilateralis, P. wheeleri, P. wolfii, P. ×gaspensis, P. ×limosa, P. ×nematophylla
P. abbreviata, P. alpina, P. alsodes, P. ammophila, P. annua, P. arachnifera, P. arctica, P. arida, P. arnowiae, P. atropurpurea, P. autumnalis, P. bolanderi, P. bulbosa, P. chaixii, P. chambersii, P. chapmaniana, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. cuspidata, P. diaboli, P. douglasii, P. eminens, P. fendleriana, P. glauca, P. hartzii, P. howellii, P. infirma, P. interior, P. keckii, P. kelloggii, P. laxa, P. laxa × glauca, P. laxiflora, P. leibergii, P. leptocoma, P. lettermanii, P. macrantha, P. macrocalyx, P. marcida, P. napensis, P. nemoralis, P. nervosa, P. occidentalis, P. paludigena, P. palustris, P. paucispicula, P. piperi, P. porsildii, P. pratensis, P. pringlei, P. pseudoabbreviata, P. reflexa, P. rhizomata, P. saltuensis, P. secunda, P. sierrae, P. stebbinsii, P. stenantha, P. strictiramea, P. sublanata, P. suksdorfii, P. supina, P. sylvestris, P. tenerrima, P. tracyi, P. trivialis, P. unilateralis, P. wheeleri, P. wolfii, P. ×gaspensis, P. ×limosa, P. ×nematophylla
Name authority L. Vasey & Scribn.
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