Poa saltuensis
Poa supina
old-pasture blue grass
supine bluegrass
20-95 cm tall, 0.8-1.5 mm thick.
8-12(20) cm, slender, bases decumbent, terete or weakly compressed;
nodes terete, 1 exserted.
closed for 1/3-2/3 their length;
ligules 0.2-3(4) mm, smooth or sparsely scabrous, truncate to obtuse;
blades 1-3.6 (6) mm wide, flat, thin, lax, veins prominent.
closed for 1/4-1/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 2-4 times blade lengths;
collars smooth, glabrous;
ligules 0.6-1 mm, smooth, glabrous, truncate;
blades 2-3 mm wide, flat, thin, soft, smooth, apices broadly prow-shaped, cauline blades subequal.
mainly pseudointravaginal.
intravaginal.
4-20(24) cm long, less than 1/4 the plant height, lax;
nodes with 1-3 branches;
branches ascending to spreading, lax, angled, angles prominent, scabrous.
2.5-5 cm, lengths 1-2 times widths, erect, loosely contracted or open, ovoid to pyramidal, sparse, with 10-25(30) spikelets and 1-2 branches per node;
branches 1-3 cm, spreading to reflexed, straight, terete, smooth or sparsely scabrous, with 2-5(8) spikelets.
3-5.6 mm, laterally compressed;
florets 2-5;
rachilla internodes glabrous, usually shorter than 1 mm.
4-6 mm, laterally compressed;
florets 3-7;
rachilla internodes smooth, glabrous, more or less concealed, distal internode less than 1/2 the length of the distal lemma.
2/3 – 3/4 as long as the adjacent lemmas, distinctly keeled;
lower glumes 1(3)-veined;
upper glumes shorter than or subequal to the lowest lemmas;
calluses webbed;
lemmas 2.4-4 mm, lanceolate to broadly lanceolate, distinctly keeled, usually glabrous, bases of marginal veins rarely sparsely softly puberulent, lateral veins prominent, intercostal regions smooth, minutely bumpy, apices obtuse to sharply acute or acuminate;
palea keels scabrous;
anthers 0.4-1.5 mm.
distinctly keeled, keels smooth;
lower glumes 1-veined;
calluses glabrous;
lemmas 1.7-4 mm, lanceolate, distinctly keeled, smooth throughout, proximal lemmas glabrous throughout or the keels and marginal veins sparsely short-villous, distal lemmas glabrous or the keels and marginal veins short-villous to near the apices, lateral veins moderately prominent, intercostal regions glabrous, margins smooth, glabrous, apices obtuse to acute;
palea keels smooth, sometimes sparsely softly puberulent to short-villous;
anthers (1.25)1.5-2.5 mm, cylindrical prior to dehiscence, those of the upper 1-2 florets commonly vestigial.
= 14.
Poa saltuensis
Poa supina
Poa saltuensis grows in woodlands of the north-central and northeastern United States and adjacent Canada, extending south to Tennessee. The two subspecies are sometimes treated as species. The variation between the two overlaps and is correlated to some extent with ecology and geography. Poa marcida (p. 512), a western species once included in P. saltuensis, differs in having closed sheaths and attenuate lemmas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Poa supina is native to boreal to alpine regions of Eurasia. Beginning in the 1990s, the cultivar 'Supernova' has been introduced for seeding in wet to moist, cool, shady areas subject to heavy traffic. It has been tested in both Canada and the United States, and is expected to gradually escape cultivation, probably becoming established throughout the cool-temperate portion of the Flora region. Its current distribution is not known. Poa supina differs from P. annua (p. 519), of which is thought to be one of the parents, in having longer anthers and a more stoloniferous habit, as well as in being diploid. It is gynomonoecious.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Anthers 0.4-1 mm long; lemma apices obtuse to acute, firm or scarious for up to 0.25 mm | subsp. languida |
1. Anthers 0.9-1.5 mm long; lemma apices acute to acuminate, scarious for 0.25-0.5 mm | subsp. saltuensis |
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