Poa sylvestris
Poa macrantha
woodland bluegrass
dune bluegrass, large flower sand dune blue grass, sand-dune blue grass, seashore blue grass
30-120 cm, bases often decumbent.
(7)15-60 cm tall, 1.5-2 mm thick, bases decumbent, terete or weakly compressed, smooth or moderately scabrous below the panicles;
nodes terete, 0(1) exserted.
closed for (1/20) 1/2-7/8 their length, terete, throats frequently ciliate near the point of fusion;
ligules 0.5-2.7 mm, smooth or sparsely scabrous, truncate to obtuse;
blades 0.7-5 mm wide, flat, thin, lax.
closed for about 1/2 their length, terete, glabrous or sparsely retrorsely scabrous, bases of basal sheaths glabrous, distal sheath lengths 1.7-4(6) times blade lengths;
collars smooth, glabrous;
ligules 1-5 mm, scabrous, truncate to acute, ciliolate;
innovation blades to 30 cm, moderately to densely scabrous or hispidulous on and between the veins;
cauline blades subequal in length, 2-4 mm wide, involute, thick, somewhat arcuate, firm, abaxial surfaces smooth or moderately to densely scabrous or hispidulous on and between the veins, apices narrowly prow-shaped, flag leaf blades 1-10 cm.
mainly pseudointravaginal.
mostly intravaginal, some extravaginal.
(6.7)9-20 cm, open, narrowly conical at maturity;
nodes with (2)3-10 branches per node;
branches (2)3-7 cm, spreading to eventually reflexed, straight, angled, angles several, densely scabrous, with 1-11 spikelets.
3-15 cm, erect, ovoid to lanceolate, contracted, often interrupted, congested, with 15-80 spikelets, rachises glabrous, smooth to moderately scabrous;
nodes with 1-2 branches;
branches 1-6 cm, erect, stiff, terete to weakly angled, smooth or sparsely to moderately scabrous, with 3-17 spikelets.
2.5-4.4 mm, laterally compressed;
florets 2-3(4);
rachilla internodes longer than (1)1.2 mm, smooth, glabrous.
9-17 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic;
florets 3-6(10);
rachilla internodes smooth, usually hairy, hairs 0.3-0.4+ mm, rarely glabrous.
distinctly keeled, keels scabrous;
lower glumes 1(3)-veined;
upper glumes shorter than or subequal to the lowest lemmas;
calluses webbed;
lemmas 2.1-3.1 mm, broadly lanceolate, distinctly keeled, keels and marginal veins short-villous, extending to near the apices on the keels, lateral veins prominent, softly puberulent to short-villous, intercostal regions usually sparsely softly puberulent, smooth, apices obtuse to acute;
palea keels softly puberulent at midlength, apices finely scabrous;
anthers 1-1.8 mm.
broadly lanceolate, subequal to the adjacent lemmas, distinctly keeled, keels sparsely scabrous near the apices;
lower glumes 3-veined;
upper glumes usually 7+ mm, 3-5-veined;
calluses usually with a crown of hairs, sometimes glabrous or diffusely webbed;
lemmas (6)7.5-11 mm, lanceolate, 5-7(11)-veined, distinctly keeled, keels and marginal veins, and sometimes the lateral veins, short-villous to softly puberulent, intercostal regions smooth or scabrous, glabrous or softly puberulent, margins glabrous, apices acute;
palea keels scabrous, intercostal regions glabrous;
anthers vestigial (0.1-0.2 mm) or (2)3-4(5) mm.
= 28.
= 28.
Poa sylvestris
Poa macrantha
Poa sylvestris grows in southeastern Canada and throughout much of the eastern United States, mainly at low elevations in woodlands, especially in riparian zones. It is easily distinguished from P. wolfii (p. 514) by its smaller, more numerous spikelets and lemmas that are usually sparsely hairy between the veins. Plants from the middle Appalachian Mountains have been confused with P. paludigena (p. 572); P. sylvestris is usually larger, has more than 2 branches per panicle node, is pubescent between the lemma veins and palea keels, and has larger anthers.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Poa macrantha is a dioecious coastal sand dune species that grows from southern Alaska to northern California. It competes better than P. douglasii (see previous) with the invasion of its habitat by Ammophila and other exotic species. It used to be treated as a subspecies of P. douglasii; a few intermediates with that species have been found around the mouth of Little River, California. Although clearly related, the two species are reasonably divergent in a number of characters. Poa macrantha is readily distinguished from P. douglasii by its glabrous rachises and usually longer glumes and lemmas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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