Plants perennial; rhizomatous, rhizomes usually well developed and extensive, sometimes poorly developed, densely to loosely tufted or the shoots solitary. Basal branching mainly extravaginal or equally extra- and intravaginal. Culms 5-120 cm, terete or weakly compressed; nodes terete or weakly compressed. Sheaths closed for (1/6)1/4 – 3/5 their length, terete to slightly compressed, smooth or sparsely scabrous, usually glabrous, infrequently sparsely to moderately hairy, distal sheaths usually longer than their blades; collars smooth, glabrous; ligules 0.9-7 mm, smooth or scabrous, truncate to acute, glabrous or ciliolate; innovation blades of intravaginal shoots involute and narrower or similar to the cauline blades and blades of extravaginal shoots; cauline blades subequal or the middle blades longest, flat, folded, or weakly involute, abaxial surfaces smooth, glabrous, adaxial surfaces smooth or sparsely scabrous, frequently sparsely hairy, hairs 0.2-0.8 mm, apices prow-shaped, sometimes narrowly prow-shaped, flag leaf blades 1.5-10 cm. Panicles 2-18(20) cm, loosely contracted to open, often slightly lax to nodding, sparsely to moderately congested, with 1-7(9) branches per node; branches 1-9 cm, ascending to widely spreading or somewhat reflexed, flexuous to straight, terete or angled, usually smooth or sparsely to moderately scabrous, infrequently densely scabrous. Spikelets 3.5-9(12) mm, lengths to 3.5 times widths, lanceolate to broadly lanceolate, laterally compressed, sometimes bulbiferous; florets 2-5(6), usually normal, bisexual; rachilla internodes smooth, glabrous or pubescent. Glumes unequal to subequal, distinctly shorter than to subequal to the adjacent lemmas, keels weak or distinct, smooth or scabrous; lower glumes 1- or 3-veined; calluses terete or slightly laterally compressed, usually dorsally webbed, sometimes with additional webs below the marginal veins, infrequently glabrous; lemmas 2-8 mm, lanceolate to broadly lanceolate, distinctly keeled, keels and marginal veins, and sometimes also the lateral veins, hairy, all veins prominent, intercostal regions glabrous or hairy; palea keels sometimes with hairs at midlength, intercostal regions glabrous or hairy; anthers 3, 1.2-2.5 mm, infrequently aborted late in development.

Discussion

Poa section Poa includes 32 species. All the species are synoecious perennials; most are strongly rhizomatous.

Selected References

None.

Lower Taxa

Poa arctica, Poa macrocalyx, Poa pratensis, Poa sublanata