Aquatic and Wetland Vascular Plants of the Northern Great Plains
63. Poaceae, the Grass Family
23. Poa L. -- Bluegrass3. Poa palustris L. -- Fowl bluegrass
Loosely tufted perennial 4-11 dm tall; culms terete, usually curved and decumbent at the base, producing roots from lower nodes and thus stolonous (simulating a short-rhizomatous base), usually purplish toward the base. Leaf blades ascending to spreading, rather lax, flat, 0.5-5 mm wide, scabrous; sheaths glabrous, rounded to slightly keeled, closed near the base; ligules mostly 1.6-5 mm long, rounded or lacerate. Panicle diffuse and loosely spreading (contracted when young and emerging from the sheath), 8-30 cm long. Spikelets 2- to 4-flowered, 2-5 mm long, 1.5-2 mm wide; glumes subequal, often purplish, lanceolate, acute, scabrous on the keel, the first glume 1.5-3 mm long, 1- to 3-nerved, the second glume 2-3.1 mm long, 3-nerved; lemmas 2-3 mm long, subacute, often purplish on the sides, bronzed at the tip, pubescent on the marginal nerves and keel toward the base, also bearing a tuft of cobwebby hairs at the base, this sometimes scant, the intermediate nerves very faint to obsolete so that the lemma appears 3-nerved; anthers 0.8-1.2 mm long. Grain brown, fusiform to narrowly ellipsoid, ca. 1 mm long. Jun--early Sep. Wet meadows, marshes, shores, stream banks, ditches and low prairie, also moist woods and hillsides; common in the n part, less so s; (Newf. and Que. to AK, s to VA, MO, NE, NM and CA; also Eurasia).
Inland bluegrass, Poa interior Rydb., is sometimes encountered on stream banks and in other moist to fairly dry habitats. It is similar to P. palustris except for its smaller stature and densely tufted nature. It can be distinguished from P. palustris by its smaller panicles, 5-15 cm long, and the shorter ligules, mostly less than 1.6 mm long.
Poa palustris (from Hitchcock 1950). |
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