Poa douglasii |
Poa ×gaspensis |
|
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Douglas' bluegrass, sand dune blue grass |
Gaspé Peninsula bluegrass |
|
Habit | Plants perennial; loosely tufted, rhizomatous and stoloniferous, rhizomes and stolons to 1 m. | Plants perennial; densely to loosely tufted, rhizomatous. |
Culms | (5)10-30 cm tall, 1.2-1.5 mm thick, bases decumbent, terete or weakly compressed, hispidulous beneath the panicles; nodes terete, 0(1) exserted. |
15-50 cm, erect or the bases decumbent. |
Sheaths | closed for about 1/2 their length, terete, smooth or sparsely to moderately retrorsely scabrous near the collars, glabrous, bases of basal sheaths glabrous, distal sheath lengths 0.9-3.5 times blade lengths; collars sparsely to moderately retrorsely scabrous, glabrous; ligules 1-2 mm, scabrous, truncate to obtuse, ciliolate; innovation blades to 30 cm long, adaxial surfaces moderately to densely scabrous or hispidulous on and between the veins; cauline blades subequal in length, 1-2 mm wide, involute, moderately thick, moderately firm, arcuate, abaxial surfaces smooth or sparsely scabrous, adaxial surfaces moderately to densely scabrous or hispidulous on and between the veins, apices narrowly prow-shaped, flag leaf blades 1-9 cm. |
closed for 1/4-1/2 their length, terete; ligules acute; blades flat, thin, apices broadly prow-shaped. |
Basal branching | mainly intravaginal, some extravaginal. |
intra- and extravaginal. |
Panicles | 1.5-6 cm, erect, compact, ovoid, contracted, infrequently interrupted, congested, with 15-50 spikelets; nodes with 1-2 branches, internodes densely hispidulous; branches 0.5-2 cm, erect, stiff, terete to weakly angled, densely hispidulous, with 1-5 spikelets. |
erect, narrowly lanceoloid to ovoid, contracted, with 2-4 branches per node; branches ascending to spreading, sparsely scabrous. |
Spikelets | 7-12 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic; florets 3-6; rachilla internodes usually shorter than 0.5 mm, smooth, glabrous. |
3.5-6 mm, laterally compressed, with 3-4 florets. |
Glumes | broadly lanceolate, 1/2 as long as to subequal to the adjacent lemmas, distinctly keeled; lower glumes 3-veined; upper glumes 4-4.5(7+) mm, 3-veined; calluses usually with a crown of hairs, sometimes glabrous or diffusely webbed; lemmas 5-7.5 mm, lanceolate, 5-veined, distinctly keeled, keels, marginal veins, and sometimes the lateral veins short- to long-villous or softly puberulent, rarely glabrous, lateral veins moderately prominent, intercostal regions smooth, glabrous, margins glabrous, apices acute; palea keels scabrous to pectinate-ciliate, intercostal regions glabrous; anthers vestigial (0.1-0.2 mm) or (2)2.5-3.5 (4) mm. |
broadly lanceolate, distinctly keeled, distinctly scabrous on the distal 1/3; lower glumes 3-veined; calluses shortly webbed; lemmas 2.5-4.5 mm, broadly lanceolate, keeled, keels and marginal veins long-villous, intercostal regions sofdy puberulent; palea keels scabrous, long-villous at midlength; anthers 1.2-1.4 mm. |
2n | = 28. |
= unknown. |
Poa douglasii |
Poa ×gaspensis |
|
Distribution |
CA
|
|
Discussion | Poa douglasii is a dioecious endemic that grows on coastal sand dunes in California, a habitat that is being invaded by exotic species. It is rare north of Mendocino. Its hairy rachises distinguish P. douglasii from all other species of Poa in the Flora region. It differs from P. macrantha (see next), which occupies similar habitats, in this and in its usually longer glumes and lemmas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa ×gaspensis is found in the coastal mountains of the Gaspe Pennisula. There are few plants that fit the description. It seems to consist of hybrids between P. pratensis subsp. alpigena (p. 525) and P. alpina (p. 518). Poa xgaspensis differs from P. alpina in its extravaginal branching, rhizomatous habit, and webbed calluses; from P. pratensis in its acute ligules and more pubescent lemmas; and from P. arctica (p. 529) in its sharply keeled, more scabrous glumes and its spikelet shape, which approaches those of P. alpina and P. pratensis. Poa ×gaspensis is a named intersectional hybrid (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 551. | FNA vol. 24. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Madropoa | Poaceae > subfam. Pooideae > tribe Poeae > Poa |
Sibling taxa | ||
Name authority | Nees | Fernald |
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