Poa macrantha
Poa sierrae
dune bluegrass, large flower sand dune blue grass, sand-dune blue grass, seashore blue grass
Sierra blue grass
(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.
20-60 cm, slender, erect or the bases decumbent, terete or weakly compressed;
nodes terete, 1-2 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 from 9/10 their length to their entire length, terete, smooth or sparsely scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 0.18-0.8 times blade lengths;
collars smooth, glabrous;
ligules 3-6 mm, scabrous, acute to acuminate;
innovation blades similar to the cauline blades;
cauline blades gradually reduced in length distally, 1.5-2.5 mm wide, flat, thin, soft, smooth or sparsely scabrous, primarily over the veins, apices narrowly to broadly prow-shaped, flag leaf blades 8-12 cm.
mostly intravaginal, some extravaginal.
extravaginal, initiated as pinkish to purplish fleshy buds that persist as sets of short scales at the nodes of rhizomes and the proximal culm nodes, drying brownish and flabelliform after the shoots develop.
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.
4-15 cm, erect, ovoid, sparse, with fewer than 15(20) spikelets;
nodes with 1-2 branches;
branches 1-4.5 cm, spreading to reflexed, slender, terete, sparsely to moderately scabrous, with 1-3 spikelets.
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.
5-9 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;
florets 2-6;
rachilla internodes smooth, sparsely hairy, hairs to 0.3 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.
1/3 – 3/4(4/5) as long as the adjacent lemmas, keels sparsely scabrous;
lower glumes 3-veined;
calluses glabrous or webbed, hairs at least 1-2 mm;
lemmas 4-7 mm, lanceolate, distinctly keeled, keels and marginal veins glabrous or short-villous, lateral veins obscure, glabrous, finely scabrous, intercostal regions glabrous or sparsely softly puberulent, margins glabrous, apices acute;
palea keels scabrous, sometimes softly puberulent at midlength;
anthers vestigial (0.1-0.2 mm) or 2-4 mm.
= 28.
= ca. 58.
Poa macrantha
Poa sierrae
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 sierrae, a distinctive dioecious species, is a narrow endemic of mid-elevation canyon slopes on the west side of the Sierra Nevada, California. It can be distinguished from all other Poa species by the scaly, pink to purplish buds on the rhizomes, and by the entirely or almost entirely closed upper culm sheaths that are shorter than their blades.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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