Poa macrantha
Poa sublanata
dune bluegrass, large flower sand dune blue grass, sand-dune blue grass, seashore blue grass
cottonball bluegrass
(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.
20-40(75) cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;
nodes terete, proximal nodes usually not exserted.
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.
closed for 2/5 – 1/2 their length, terete, glabrous, smooth or slightly scabrous, bases of basal sheaths glabrous, distal sheath lengths (1)1.2-3.5 times blade lengths;
collars smooth, glabrous;
ligules 1.5-4(6) mm, smooth, apices obtuse to acute, not ciliate;
blades 1-3.5(5) mm wide, folded or flat, innovation shoot blades involute, soft, abaxial surfaces glabrous, adaxial surfaces smooth or sparsely scabrous, frequently sparsely hairy with 0.2-0.8 mm hairs, slender, erect to appressed, curving, sinuous or straight, apices narrowly prow-shaped, cauline blades subequal, flag leaf blades 1.5-8 cm.
mostly intravaginal, some extravaginal.
mainly extravaginal.
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.
5-9(17) cm, narrowly lanceoloid to narrowly pyramidal, loosely contacted to open, sparse, with 25-60 spikelets and 2-5 branches per node;
branches 1-3 cm, ascending to spreading, slightly flexuous to fairly straight, terete, smooth or sparsely scabrous, usually with 1-5 spikelets per branch, the spikelets moderately crowded in the distal 1/2.
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.
4-6.5(8) mm, lengths to 3 times widths, laterally compressed;
florets 2-4(6);
rachilla internodes shorter than 1 mm, smooth, usually glabrous, rarely with a few hairs.
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.
unequal to subequal, usually distinctly shorter than the adjacent lemmas, lanceolate, distinctly keeled, keels smooth to sparsely scabrous;
lower glumes 2.8-3.5 mm, narrowly lanceolate, (1)3-veined;
upper glumes 4-4.5(5) mm, distinctly shorter than to nearly equaling the lowest lemmas;
calluses dorsally webbed, webs copious, hairs at least 1/2 times the lemma length, sometimes secondary webs present under the marginal veins;
lemmas 3.7-4.5(5) mm, lanceolate, usually strongly purple, distinctly keeled, keels, lateral veins, and marginal veins copiously hairy, hairs cottony, lateral veins prominent, less hairy, intercostal regions glabrous, usually smooth or finely muriculate, sometimes sparsely scabrous distally, margins narrowly hyaline, glabrous, apices acute;
palea keels sparsely scabrous, long-villous at midlength, intercostal regions narrow, glabrous;
anthers 1.8-2.5 mm.
= 28.
= 56, ca. 70.
Poa macrantha
Poa sublanata
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.)
Poa sublanata grows in the high arctic of Alaska and Russia, usually on sandy ground. Bulbiferous plants are known from Russia; none have been found in the Flora region.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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