Arrhenatherum elatius

Species category

Revegetation or Rangeland

Common name

tall oatgrass

Diagnostic characters

Planting unit

FloretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.

Shape

Lanceolate

Size

  • Length: 6.5 mm
  • Width: 1 mm
  • Thickness: 1 mm

Color

Yellow

Texture

ScabrousScabrous:
Rough to the touch, covered with minute points of very short, stiff hairs.
across the tip of the lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
and scattered long hairs

Lemma

Papery with nerves green near the distal end

Palea

Papery mostly obscured by enfolding lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.

Other structures

Long geniculateGeniculate:
Bent at a sharp angle.
awn and strong bristles surrounding callusCallus:
The hard base of grass florets or spikelets, just above the point of disarticulation.
.

Identification notes

PaleaPalea:
One of the thin bracts of grass floret enclosing the fruit (caryopsis) that is located on the side opposite the embryo.
tend to spread away from the lemmasLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
at the distal end. Hulled caryopsesCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).
are approximately four to five mm long and nearly cylindrical in shape. FloretsFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
and caryopsesCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).
are not very different from species of the same genus.

Noxious weed seed categories

Not listed

AOSA examination list

Included

Nomenclature

Family

Poaceae

Valid name

Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl

 Arrhenatherum elatius.  Achene with a long geniculate awn and strong bristles surrounding the callus. 
Arrhenatherum elatius. Achene with a long geniculate awn and strong bristles surrounding the callus. 
 Arrhenatherum elatius . Floret pair. Photo courtesy of USDA-APHIS-PPQ.
Arrhenatherum elatius. Floret pair. Photo courtesy of USDA-APHIS-PPQ.