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Plant Profile  
FYUSE 3D Image

Common Name: Annual Threeawn

Other Names: Oilfield Threeawn, Prairie Threeawn

Species Name: Aristida oligantha

Plant Type: Grasses & Grass-like

Family Name: Poaceae, Grass Family

Tribe: Aristideae, Threeawn Tribe





Plant Facts  
Origin Native
Duration Annual
Season Warm
Distribution in the U.S. East Coast to the Great Plains and adventive in Arizona, California and Oregon
Distribution in Oklahoma Throughout the state



ID Characteristics

  • Field Identification Characteristics


    • Hairs at junction of blade and sheath
    • Branching at the nodes


    • Large seed heads with three long awns per floret
    • Glumes equal length
    • No stalk (pedicel) attaching spikelet to stem
  • Leaf and Stem Characteristics
    • Plant Height: 15-60 centimeters
    • Ligule Type: Ciliate-membranous
    • Sheath: Glabrous (except for a few hairs at apex)
    • Leaves: Cauline
  • Floral Characteristics
    • Inflorescence Type: Panicle
    • Florets Per Spikelet: 1
    • Glumes: Equal



Soil Type Bare gravel, sand or clay
Habitat Disturbed sites
Successional Stage Early



Grazing Little forage value to livestock. Fair to poor forage quality in early growth. Awns can injure the eyes of livestock and decrease the value of wool in sheep. Decreases value of hay when present.
Wildlife Little usable forage for wildlife. The sharp ends of the seeds can cause infections in the eyes of wildlife. Only sometimes consumed by songbirds, bobwhite quail, and small mammals when other sources of food are not available. Jackrabbits and pronghorn will sometimes consume plants when they are actively growing. Does not provide forage for white-tailed deer. Smith’s longspur can often be found nearby in winter months. It does not provide quality protective cover for many species of wildlife.



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