Selected Plants of Navajo Rangelands

Take care of our Navajo Rangelands

Three-awns, annual

Dry seeds and awns of Aristida adscensionis

Three-awns are grasses that occur in both annual and perennial forms. On Navajo rangelands, the annual three-awn species are six weeks three-awn (Aristida adscensionis) and oldfield three-awn (Aristida oligantha). Three-awns are native to the United States.

They are not considered a valuable forage species, though they do provide some habitat for birds and other small animals. The awns can tend to catch in the wool or irritate the skin of livestock.

These bunchgrasses are many-branched toward the base of the clump, and they grow to a height of about three feet. The leaves roll inward. The florets and awns of the inflorescences spread outward, creating a brushy appearance. There are three awns on each floret.

Dry spike of Aristida adscensionis with multiple florets, each with three awns
Herbarium specimen showing base, stems, leaves, and inflorescences of Aristida oligantha
Herbarium specimen showing base, stems, leaves, and inflorescences of Aristida oligantha

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