The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Howell's blue grass

Habit Plants usually annual, rarely longer-lived; densely tufted, tuft bases narrow; not stoloniferous, not rhizomatous. Plants annual or perennial; sometimes unisexual; with or without rhizomes or stolons, densely to loosely tufted or the culms solitary.
Culms

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

nodes terete, usually 1-2 exserted.

spindly to stout, terete or weakly to strongly compressed;

nodes 0-5, 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.

terete or weakly to strongly compressed, closed only at the base or up to full length, fusion of the margins not extended by a hyaline membrane, basal sheaths usually glabrous, rarely sparsely retrorsely strigose, hairs about 0.1 mm;

ligules 0.1-18 mm, thinly membranous and white to milky white or hyaline, truncate to acuminate, entire or erose to lacerate, smooth or ciliolate;

blades flat, folded, or involute, thin to thick, smooth or sparsely to densely scabrous, adaxial surfaces glabrous or hairy, hispidulous or puberulent, apices narrowly to broadly prow-shaped.

Basal branching

intravaginal.

intra- and/or extravaginal or pseudointravaginal.

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.

1-41 cm, erect to nodding or lax, tightly contracted to open, with 1-100+ spikelets;

branches 0.5-20 cm, erect to reflexed, terete or angled, smooth or sparsely to densely scabrous, usually glabrous, rarely hispidulous, with 1 to many spikelets.

Spikelets

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

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

2-12 mm, subterete to strongly laterally compressed, sometimes bulbiferous;

florets (1)2-8(13);

rachilla internodes smooth or scabrous, glabrous or pubescent.

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.

shorter than to slightly exceeding the adjacent lemmas, weakly to distinctly keeled, smooth or scabrous;

calluses blunt, usually terete or slightly laterally compressed, sometimes slightly dorsally compressed, glabrous, dorsally webbed, diffusely webbed, or with a crown of hairs;

lemmas 1.7-11 mm, rounded to weakly or distinctly keeled, thinly membranous to chartaceous, glabrous or hairy on the keel and veins, sometimes the intercostal regions also hairy, 5-7(11)-veined, margins smooth or scabrous, glabrous, apices obtuse to acuminate;

palea keels usually scabrous, infrequently smooth, glabrous or with hairs;

anthers (1-2)3, 0.1-4.5(5) mm.

2n

= unknown.

Poa howellii

Poa subg. Poa

Distribution
from FNA
CA; OR; WA; BC
[WildflowerSearch map]
[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 subg. Poa is the largest subgenus of Poa. Its distribution is essentially the same as that of the genus. It includes all but one of the 70 species of Poa in the Flora region; P. etninens is included in subg. Arctopoa.

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

Source FNA vol. 24, p. 534. FNA vol. 24.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa Poaceae > subfam. Pooideae > tribe Poeae > 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
Subordinate taxa
Synonyms P. bolanderi var. howellii
Name authority Vasey & Scribn. unknown
Web links