Poa douglasii
Poa interior
Douglas' bluegrass, sand dune blue grass
inland bluegrass, interior blue grass, woods blue grass
(5)10-30 cm tall, 1.2-1.5 mm thick, bases decumbent, terete or weakly compressed, hispidulous beneath the panicles;
nodes terete, 0(1) exserted.
5-80 cm, usually slender, mostly erect or ascending, several to many arising together;
nodes terete or slightly compressed, (0)1-2(3) exserted, top node usually at 1/3 – 3/5 the culm length.
closed for about 1/2 their length, terete, smooth or sparsely to moderately retrorsely scabrous near the collars, glabrous, bases of basal sheaths glabrous, distal sheath lengths 0.9-3.5 times blade lengths;
collars sparsely to moderately retrorsely scabrous, glabrous;
ligules 1-2 mm, scabrous, truncate to obtuse, ciliolate;
innovation blades to 30 cm long, adaxial surfaces moderately to densely scabrous or hispidulous on and between the veins;
cauline blades subequal in length, 1-2 mm wide, involute, moderately thick, moderately firm, arcuate, abaxial surfaces smooth or sparsely scabrous, adaxial surfaces moderately to densely scabrous or hispidulous on and between the veins, apices narrowly prow-shaped, flag leaf blades 1-9 cm.
closed for 1/10 – 1/5 their length, terete, bases of basal sheaths glabrous, distal sheath lengths (0.6)0.88-1.64 times blade lengths;
ligules 0.5-1.5(3) mm, sparsely to densely scabrous, apices truncate to obtuse, ciliolate;
blades 0.8-3 mm wide, mostly flat, thin, soft, appressed or abruptly ascending to spreading, straight or somewhat lax, apices narrowly prow-shaped.
mainly intravaginal, some extravaginal.
all or mostly extravaginal.
1.5-6 cm, erect, compact, ovoid, contracted, infrequently interrupted, congested, with 15-50 spikelets;
nodes with 1-2 branches, internodes densely hispidulous;
branches 0.5-2 cm, erect, stiff, terete to weakly angled, densely hispidulous, with 1-5 spikelets.
(1.5)3-15(17) cm, lengths generally 2.5-4 times widths at maturity, usually erect, lax in shade forms, narrowly lanceoloid to ovoid, sparsely to moderately congested;
nodes with 2-5 branches;
branches 0.4-8(9) cm long, 1/4-1/2 the panicle length, ascending to widely spreading, fairly straight, slender to moderately stout, angled, angles moderately to densely scabrous.
7-12 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic;
florets 3-6;
rachilla internodes usually shorter than 0.5 mm, smooth, glabrous.
3-6 mm, lengths 2-3 times widths, lanceolate to narrowly ovate, laterally compressed, usually not glaucous;
florets (1)2-3(5);
rachilla internodes usually shorter than 1 mm, smooth, muriculate, or scabrous, glabrous, hispidulous, or sparsely to densely puberulent, proximal internodes frequently curved.
broadly lanceolate, 1/2 as long as to subequal to the adjacent lemmas, distinctly keeled;
lower glumes 3-veined;
upper glumes 4-4.5(7+) mm, 3-veined;
calluses usually with a crown of hairs, sometimes glabrous or diffusely webbed;
lemmas 5-7.5 mm, lanceolate, 5-veined, distinctly keeled, keels, marginal veins, and sometimes the lateral veins short- to long-villous or softly puberulent, rarely glabrous, lateral veins moderately prominent, intercostal regions smooth, glabrous, margins glabrous, apices acute;
palea keels scabrous to pectinate-ciliate, intercostal regions glabrous;
anthers vestigial (0.1-0.2 mm) or (2)2.5-3.5 (4) mm.
lanceolate to broadly lanceolate, distinctly keeled, keels smooth or sparsely scabrous;
lower glumes 3-veined, long- or abruptly tapered to a slender point, lengths 4.5-6.3 times widths;
calluses usually webbed, infrequently glabrous in depauperate alpine specimens, webs usually scant, less than 1/2(2/3) the lemma length, frequently minute;
lemmas 2.4-4 mm, lanceolate, distinctly keeled, straight or gradually arched, not abruptly inwardly arched at the junction with the scarious apices, keels and marginal veins short-villous, hairs extending 2/3 – 3/4 the keel length, lateral veins usually glabrous, rarely sparsely puberulent, obscure, intercostal regions smooth, sometimes weakly muriculate, glabrous, margins not or slightly inrolled, glabrous, apices acute, usually partially bronze-colored;
palea keels scabrous, intercostal regions glabrous;
anthers (1.1)1.3-2.5 mm.
= 28.
= 28, 42, 56.
Poa douglasii
Poa interior
Poa douglasii is a dioecious endemic that grows on coastal sand dunes in California, a habitat that is being invaded by exotic species. It is rare north of Mendocino. Its hairy rachises distinguish P. douglasii from all other species of Poa in the Flora region. It differs from P. macrantha (see next), which occupies similar habitats, in this and in its usually longer glumes and lemmas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Poa interior, a native species, grows from Alaska to western Quebec and New York, south to Arizona and New Mexico. It is restricted to the Flora region. It is fairly common from boreal forests to low alpine habitats of the Rocky Mountains. It grows in subxeric to mesic habitats, such as mossy rocks and scree, usually in forests. It is usually tetraploid.
In alpine habitats, Poa interior is often quite short, and often sympatric with P. glauca (see next). It is most reliably distinguished from P. glauca by lemmas that are glabrous between the marginal veins and keels or, rarely, sparsely puberulent on the lateral veins. It usually also differs from P. glauca subsp. rupicola in having at least a few hairs on its calluses. It can be distinguished from P. nemoralis (see previous) by its longer ligules, lower top culm node, and wider glumes and lemmas. It is sometimes difficult to distinguish from P. palustris (p. 574), but differs in having lemmas with wider hyaline margins and straight or gradually arched keels, a densely tufted habit, and scantly webbed calluses.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
BC
WA
Flora NW
PNW Herbaria
