Northern Prairie Wildlife Research Center


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Northeast Wetland Flora

Field Office Guide to Plant Species

Rough Bluegrass
Poa trivialis L.

JPG -- Species Photo JPG -- Distribution Map

Family: Grass (Gramineae)
Flowering: June-August
Field Marks: This bluegrass is characterized by its lemmas which are cobwebby at the base and hairy on the keel, but smooth on the nerves. The stem beneath the panicle is rough to the touch.
Habitat: Damp soil.
Habit: Tufted perennial herb with thickened rootstocks but without rhizomes.
Stems: Upright or spreading at the base and rooting at the nodes, weak, usually unbranched, rough to the touch, at least below the panicle, up to 3 1/2 feet tall.
Leaves: Elongated, flat, up to 1/4 inch wide, smooth or rough to the touch; sheaths rough to the touch.
Flowers: Borne in spikelets, the spikelets arranged in panicles up to 8 inches long; spikelets 2- to 3-flowered, up to 1/4 inch long, on rough stalks.
Glumes: Lanceolate, pointed at the tip, smooth, up to 1/6 inch long.
Lemmas: Narrowly ovate, pointed at the tip, up to 1/6 inch long, hairy on the keel but not on the nerves, cobwebby hairy at the base.
Sepals: 0.
Petals: 0.
Stamens: 3.
Pistils: Ovary superior, smooth.
Fruits: Grains ellipsoid to obovoid, smooth.
Notes: Gleason and Cronquist call this family Poaceae.

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U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/florane/species/2/poatriv.htm
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Page Last Modified: Thursday, 03-Aug-2006 11:39:25 EDT
Reston, VA [vaww55]