Poa paludigena |
Poa douglasii |
|
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bog bluegrass, eastern bog bluegrass |
Douglas' bluegrass, sand dune blue grass |
|
Habit | Plants perennial; usually pale green; loosely tufted, slender, usually neither stoloniferous nor rhizomatous, occasionally with short, slender rhizomes. | Plants perennial; loosely tufted, rhizomatous and stoloniferous, rhizomes and stolons to 1 m. Basal branching mainly intravaginal, some extravaginal. |
Culms | 10-55 cm, very slender, weak. |
(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. |
Sheaths | closed for 1/4 - 3/5 their length, terete, smooth or sparsely scabrous, margins not ciliate; ligules 0.5-2 mm, smooth or sparsely scabrous, truncate; blades 0.8-2 mm wide, flat, thin, soft, apices narrowly prow-shaped. |
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. |
Basal branching | mostly extravaginal. |
|
Panicles | 3-8(12) cm, lax, open, sparse; nodes with 1-2(3) branches; branches (2)3-7 cm, spreading to reflexed, capillary, angled, angles scabrous. |
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. |
Spikelets | 3.2-5.2 mm, laterally compressed, broadly lanceolate to ovate; florets 2-3(5); rachilla internodes smooth, glabrous. |
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. |
Glumes | narrowly lanceolate to lanceolate, thin, distinctly keeled, keels scabrous; lower glumes 1-3-veined; upper glumes shorter than or subequal to the adjacent lemmas; calluses sparsely webbed; lemmas 2.5-4 mm, lanceolate, green, distinctly keeled, keels and marginal veins short-villous, extending 2/3 – 4/5 the keel length, lateral veins fairly prominent, intercostal regions glabrous, apices obtuse to broadly acute, white, faintly bronze-colored or not; palea keels scabrous; anthers 0.2-0.8 mm. |
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. |
2n | = unknown. |
= 28. |
Poa paludigena |
Poa douglasii |
|
Distribution |
IA; IL; IN; MI; MN; NC; NJ; NY; OH; PA; VA; WI; WV
|
CA
|
Discussion | Poa paludigena is an inconspicuous species restricted to the northeastern United States. It grows in shady bogs and fens, often underneath other plants. Poa trivialis (p. 568) sometimes grows with P. paludigena; the former has distinctly longer ligules and anthers. Plants from the middle Appalachian Mountains are sometimes confused with P. sylvestris (p. 512). Poa paludigena is generally shorter and more slender, has shorter panicles with only 1-2 branches per node, is glabrous between the lemma veins and on the palea keels, has shorter anthers, and grows in colder habitats. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 24, p. 572. | FNA vol. 24, p. 551. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Oreinos | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Madropoa |
Sibling taxa | ||
Name authority | Fernald & Wiegand | Nees |
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