Scientific Name
Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl
Common Name(s)
Tall oatgrass
Tribe / Family Name
Poeae
Flowering Period
June to August
Symbol
AREL3
Description
Tall oatgrass is an introduced cool-season perennial bunchgrass, that is sometimes rhizomatous; occasionally forms a bulbous base. Culms usually range from 50–140 cm in height. Its inflorescence is a narrow to open panicle usually 7–30 cm long with short, whorling branches clustered at the nodes, green and shiny, becoming straw-colored, and occasionally purple-tinged. Spikelets are 7–11 mm long, narrowly lance-shaped, 2-flowered (the lower floret staminate and the upper floret bisexual, pistillate, or occasionally rudimentary), and awned (the lower lemma awns 10–20 mm long, attached at mid-length, and twisted and geniculate; the upper lemma awns absent or up to 5 mm long, straight, and attached just below the tips). Ligules are 1–3 mm long, membranous, obtuse to truncate, and usually ciliate.
General Info
Tall oatgrass can be found along roadsides, fencerows, streambanks, and forest margins, in pastures, cultivated fields, wet meadows, rocky outcrops, and montane sites.
Similar Species
Tall oatgrass is very distinctive and probably won’t be confused with other grasses. However, when comparing this species with other grasses, remember its tall stature and its often shining, narrow to open panicle inflorescence, as well as its lemma awns, which are at different lengths.
Picture of growth habit.
Inflorescence is a narrow to open-panicle.
Close-up picture of spikelet.
Close-up picture of ligule.
Illustration of tall oatgrass. USDA-NRCS PLANTS Database / Hitchcock, A.S. (rev. A. Chase). 1950. <i>Manual of the grasses of the United States.</i> USDA Miscellaneous Publication No. 200. Washington, DC.