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Howell's blue grass

Wasatch bluegrass

Habit Plants usually annual, rarely longer-lived; densely tufted, tuft bases narrow; not stoloniferous, not rhizomatous. Plants perennial; loosely tufted or with solitary shoots, short-rhizomatous.
Culms

(10) 25-80(120) cm tall, 0.4-1.75 mm thick, usually erect;

nodes terete, usually 1-2 exserted.

(15)30-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-3 exserted.

Sheaths

closed for 1/2 - 7/8 their length, usually weakly compressed and keeled, usually scabrous, rarely smooth;

ligules 1.5-5(10) mm, smooth or scabrous, acute;

blades 1-7(10) mm wide, flat, lax, soft, finely scabrous, apices narrowly prow-shaped, cauline blades 2-10 cm.

closed for 1/2 - 9/10 their length, compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1-3 times blade lengths;

collars smooth, glabrous;

ligules 0.5-4 mm, smooth or sparsely scabrous, truncate to obtuse;

innovation blades similar to the cauline blades;

cauline blades 2-5 mm wide, flat, thin, smooth or sparsely scabrous mainly over the veins, apices broadly prow-shaped, middle and upper cauline blades subequal in length, flag leaf blades (2.5)4-7(11) cm long.

Basal branching

intravaginal.

all or mostly extravaginal.

Panicles

10-25(30) cm, erect, eventually open, with (1)3-5(7) branches per node;

branches eventually spreading or reflexed, fairly straight, angled, angles usually moderately to densely scabrous, rarely sparsely scabrous.

(5)12-22 cm, usually narrowly pyramidal, open, sparse, with 20-70 spikelets, proximal internodes usually (3.5)4+ cm, with 2-3(4) branches per node;

branches 3-8 cm, spreading to eventually reflexed, terete or weakly angled, sparsely to moderately scabrous, with 3-12 spikelets.

Spikelets

(2)4-6 mm, laterally compressed, with 2-5 florets;

rachilla internodes about 1 mm, smooth, usually softly puberulent, infrequently glabrous.

5-9 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-6;

rachilla internodes smooth, glabrous, distal internodes 1+ mm.

Glumes

slightly unequal, lanceolate, distinctly keeled, keels and sometimes the lateral veins sparsely to moderately scabrous;

lower glumes 1-3-veined;

upper glumes shorter than or subequal to the lowest lemmas;

calluses of some or all florets sparsely webbed;

lemmas 2.5-3.5 mm, lanceolate to narrowly lanceolate, distinctly keeled, crisply puberulent proximally, hairs evenly distributed, finely scabrous distally, lateral veins obscure to prominent, margins narrowly hyaline, glabrous, apices narrowly acute, infrequently anthocyanic;

palea keels sparsely scabrous, glabrous or softly puberulent at midlength, intercostal regions usually softly puberulent;

anthers 3, 0.2-1 mm.

lanceolate, distinctly keeled;

lower glumes 1-3-veined;

calluses glabrous;

lemmas 3-6.5 mm, lanceolate, distinctly keeled, keels and marginal veins glabrous or short-villous to softly puberulent to 1/3 their length, lateral veins obscure, intercostal regions glabrous or sparsely hispidulous, rarely softly puberulent, smooth or sparsely finely scabrous, margins glabrous, apices acute;

palea keels scabrous, glabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm) or (1.3)2-3.6 mm.

2n

= unknown.

= unknown.

Poa howellii

Poa arnowiae

Distribution
from FNA
CA; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; UT; WY
[BONAP county map]
Discussion

Poa howellii grows primarily on rocky banks and wooded slopes, from the coastal ranges of southern British Columbia to southern California. It differs from P. bolanderi (see above) in having puberulent, rather than smooth or scabrous, lemmas, and in growing at lower elevations, mostly from near sea level to 1000 m.

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

Poa arnowiae grows in openings within the coniferous forests of the mountain ranges in southeastern Idaho, northern Utah, and adjacent Wyoming. It is sequentially gynomonoecious.

Poa arnowiae used to be called Poa curta Rydb., but the type of P. curta belongs in P. wheeleri.

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

Source FNA vol. 24, p. 534. FNA vol. 24, p. 543.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Poa
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. 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
P. abbreviata, P. alpina, P. alsodes, P. ammophila, P. annua, P. arachnifera, P. arctica, P. arida, 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. 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
Synonyms P. bolanderi var. howellii P. curta
Name authority Vasey & Scribn. Soreng
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