Culms 45-100 cm. Blades 10-25 cm, involute or flat. Panicles (12)14-30 cm; primary branches usually erect, without axillary pulvini, stiff, straight, lower nodes associated with 2-10 spikelets. Glumes tan to brown, fading to stramineous. Lower glumes 5-10 mm; upper glumes 9-16 mm; lemmas 8-14 mm long, narrowing to 0.2-0.3 mm wide; awns (8)20-35 mm long, 0.2-0.3 mm wide at the base, lateral awns usually subequal to the central awn, rarely 1-3 mm. 2n = 22, 44, 66.

Aristida purpurea var. wrightii grows on sandy to gravelly hills and flats from the southwestern United States to southern Mexico. It is the most robust variety of A. purpurea, and has dark, stout awns and long panicles. It may be confused with var. nealleyi, which has narrower lemmas and awns and a light-colored panicle, but it also intergrades with var. purpurea and var. parishii. Aristida purpurea forma brownii (Warnock) Allred & Valdés-Reyna refers to plants with short central awns and lateral awns that are only 1-3 mm long.

Common Name: Wright's threeawn

Duration: Perennial

Nativity: Native

Lifeform: Graminoid

General: Erect stout stems 45-100 cm.

Vegetative: Blades distributed well above the base, 10-25 cm, involute or flat.

Inflorescence: Panicle 14-30 cm, branches erect, occasionally drooping or spreading; primary branches stiff, straight, lower nodes associated with 2-10 spikelets; glumes unequal, tan to brown, fading to stramineous, lower 5-10 mm long, upper 10-16 mm long; lemmas 8-14 mm long, narrowing to less than 0.5 mm wide, glabrous or variously pubescent, awns 2-3.5 cm long, lateral awns usually subequal to central awn.

Ecology: Found on sandy to gravelly hills and flats from 1,500-5,000 ft (457-1524 m); flowers whenever moisture is sufficient.

Notes: The most robust of the varieties with dark, stout awns and long panicles, can be confused with var. nealleyi which has narrower lemmas and awns and a light colored panicle, and is distinguished from var. purpurea by virtue of the tan to dark brown panicle where var. purpurea has a reddish panicle.

Ethnobotany: Unknown

Etymology: Aristida is from the Latin arista for awn, while purpurea is Latin for purple, wrightii is named for Charles Wright (1811-1885) an American botanical collector.

Synonyms: Aristida wrightii

Editor: SBuckley, 2010