Northern Prairie Wildlife Research Center


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Aquatic and Wetland Vascular Plants of the Northern Great Plains

63. Poaceae, the Grass Family

23. Poa L. -- Bluegrass

4. Poa pratensis L. -- Kentucky bluegrass

Strongly rhizomatous, sod-forming perennial (2)3-8(12) dm tall, the foliage green or slightly glaucous; culms erect, terete to slightly flattened, not 2-edged. Leaf blades flat to involute-folded, 0.5-4 mm wide, glabrous or seldom lightly pubescent on the upper surface, often slightly scabrous on the margins; sheaths glabrous, rounded to slightly keeled, closed in the lower 1/2; ligules 0.5-1.5(2) mm long, truncate. Panicles usually open, often pyramidal, 3-13 cm long, the branches spreading to ascending, usually numbering 4-5 at the lowest node, the spikelets crowded on the branches so that the panicle is somewhat condensed. Spikelets 2- to 6-flowered, green or purplish, compressed, 3-5 mm long, 1.5-3 mm wide; glumes ovate-lanceolate to lanceolate, scabrous on the keel, mostly unequal, the first glume 1.8-3 mm long, 1- to 3-nerved, acute, the second glume 2.2-3.8 mm long, 3-nerved, acuminate; lemmas 2-3.8 mm long, strongly keeled, acute, sericeous on the keel and marginal nerves toward the base, also with a prominent tuft of cobwebby hairs at the base, glabrous or scabrous above on the keel, often marked with purple on the sides or margins, white or lightly bronzed at the tip, the intermediate nerves usually evident; anthers 1-1.8 mm long. Grain brown, ellipsoid, ca. 1.5 mm long, the lemma and palea adherent to it. May--Aug. Wet meadows, shores, stream banks and a great variety of moist to dry habitats, ubiquitous and often abundant, introduced for lawns and pastures but possibly native as well; (Eurasia, most of Canada and the U.S.).

Poa pratensis (from Hitchcock 1950).

Map key

Previous Section -- Poa palustris L. -- Fowl bluegrass
Return to Family -- Poaceae - The Grass Family
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