Poa glauca
Poa tenerrima
glaucous blue grass, timberline bluegrass, white bluegrass
delicate blue grass
5-40(80) cm, erect to spreading, straight, wiry, bases straight or slightly decumbent;
nodes terete or slightly compressed, usually 0-1 exserted, top node at 1/10-1/3 the culm length.
15-50 cm tall, slender, 0.8-0.9 mm thick;
nodes terete, 0-1 exserted.
closed for 1/10 – 1/5 their length, terete, bases of basal sheaths glabrous or sparsely minutely hairy, hairs 0.1-0.2 mm, distal sheath lengths 1.1-4 times blade lengths;
ligules 1-4(5) mm, sparsely to densely scabrous, apices obtuse to acute, minutely ciliolate;
blades 0.8-2.5 mm wide, flat or folded, thin, soft, appressed or abruptly ascending to spreading, straight, apices narrowly prow-shaped.
closed for 76-74 their length, terete, scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 2.3-7.7 times blade lengths;
collars sparsely scabrous, glabrous;
ligules 0.5-1.5(2.5) mm, scabrous, apices usually truncate to obtuse, sometimes acute, ligules of innovations to 0.5 mm;
innovation blades filiform;
cauline blades gradually reduced in length upwards, 0.4-1.5 mm wide, mostly folded, thin, soft, soon withering, scabrous, apices narrowly prow-shaped.
all or mostly extravaginal.
intravaginal.
1-10(20) cm, lengths 3-5 times widths at maturity, rarely racemelike with branches of irregular length, erect, narrowly lanceoloid to ovoid, contracted to somewhat open, sparse, proximal internodes shorter than 1.5(4) cm;
nodes with 2-3(5) branches;
branches erect, ascending or weakly spreading, fairly straight, short, stout, angled, angles moderately to densely scabrous, rarely only scabrous distally, glaucous;
pedicels usually shorter than the spikelets.
5-15 cm, 1.3-2.2 times the branch lengths, erect, broadly rhomboidal to pyramidal, open, purple, sparse, proximal internodes 1.5-4.2 cm;
nodes with 1-2(5) branches;
branches 3-8.5 cm, widely spreading, capillary, straight, terete to weakly angled, moderately to mostly densely scabrous, with 3-9 spikelets in the distal 73.
3-7(9) mm, lengths 2-3 times widths, laterally compressed, rarely bulbiferous, usually glaucous;
florets 2-5, rarely bulb-forming;
rachilla internodes to 1.2 mm, smooth, muriculate, or scabrous, glabrous or sparsely to densely hispidulous or puberulent.
5-8 mm, lengths (3.8)4-5 times widths, usually narrowly lanceolate to lanceolate, subterete to weakly laterally compressed, drab, usually strongly anthocyanic;
florets 3-5;
rachilla internodes 1-1.5+ mm, terete or slightly dorsally compressed, muriculate or scabrous.
subequal, narrowly to broadly lanceolate, distinctly keeled, keels smooth or sparsely scabrous, apices acute;
lower glumes 3-veined;
upper glumes 2-3.8(5.2) mm, lengths usually more than 4.1 times widths, distinctly shorter to subequal to the lowest lemmas;
calluses glabrous or webbed, webs from minute to more than 1/2 the lemma length;
lemmas 2.5-4 mm, lanceolate to broadly lanceolate, distinctly keeled, keels and marginal veins short-villous, lateral veins obscure, usually sparsely softly puberulent to short-villous, intercostal regions smooth, sometimes weakly muriculate, glabrous or puberulent, margins glabrous, apices usually partially bronze-colored, obtuse or acute;
palea keels scabrous, glabrous or softly puberulent at midlength, intercostal regions glabrous or softly puberulent;
anthers (1)1.2-2.5 mm, mature sacs 0.2 mm wide, rarely aborted late in development.
lanceolate, distinctly shorter than the adjacent lemmas, scabrous distally, keels indistinct, scabrous, obtuse to acute;
lower glumes 3-veined;
calluses glabrous or with a crown of hairs, hairs to 0.3 mm;
lemmas 3-4.2 mm, lanceolate, weakly keeled, keels, veins, and proximal 2/3 of the intercostal regions puberulent, lateral veins obscure, margins strongly inrolled below, broadly scarious above, glabrous, apices obtuse to acute;
palea keels scabrous, sometimes hairy at midlength;
anthers 1.6-2.1 mm.
= 34, 42, 44, 47, 48, 49, 50, 56, 56, 57, 58, 60, 63, 64, 65, 70, 75, 78, ca. 100.
= 42.
Poa glauca
Poa tenerrima
Poa glauca is a common, highly variable, circumboreal, boreal forest to alpine and high arctic species. It grows from Alaska to Greenland, south to California and New Mexico in the west, and through Canada and the northeastern United States in the east. It also grows at scattered locations in Patagonia. It generally favors dry habitats and tolerates disturbance well. It can be distinguished from P. nemoralis (p. 574) and P. interior (see previous) by its longer ligules, lower top culm node, and wider glumes and lemmas. It can be difficult to distinguish from P. laxa subsp. banffiana (p. 570). Poa glauca is often confused in herbaria with P. abbreviata subsp. pattersonii (p. 582). It differs in having primarily extravaginal branching and, usually, longer anthers. It hybridizes with P. laxa, forming P. laxa x glauca (p. 572). It is also known to hybridize with P. hartzii (p. 589), and is suspected to hybridize with P. arctica (p. 529) and P. secunda (p. 586). It is highly polyploid, and presumed to be highly apomictic.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Poa tenerrima is a rare species, endemic to serpentine barrens along the western base of the Sierra Nevada. It differs from P. secunda subsp. secunda (see previous) in combining consistently wide, open panicles, very scabrous branches, short-truncate ligules, and very fine foliage. A series of small, delicate, open-panicled plants from the California Coast Ranges, formerly included in P. tenerrima by Soreng (1993), differ in having smooth branches and longer ligules, and are better referred to P. secunda subsp. secunda. No intergradation is evident where the two taxa grow together. Plants from the Columbia River Gorge in Oregon, including the type of P. multnomae Piper, approach P. tenerrima, but are presumed to be derived from hybridization between P. nervosa (p. 545) and P. secunda (p. 586).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. All or some spikelets bulbiferous | var. pekulnejensis |
1. Spikelets not bulbiferous. | → 2 |
2. Calluses usually webbed, sometimes glabrous; lemmas glabrous or hairy between the veins | subsp. glauca |
2. Calluses glabrous; lemmas hairy between the veins | subsp. rupicola |
BC
OR
WA
CalFlora
Flora NW
Go Botany
MI Flora
MN Wildflowers
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
