Thornber yucca

Yucca brevifolia Schott ex Trelease, Rep. (Annual) Missouri Bot. Gard. 13: 100, plates 57–59. 1902, not Engelmann 1871; Y. arizonica McKelvey; Y. confinis McKelvey; Y. thornberi McKelvey; Y. treleasei J. F. Macbride 1918, not Sprenger 1906

Plants caulescent. Stems 1–24, aerial, often branched, some reaching 2 m. Leaf margins filiferous. Inflorescences arising almost completely within to mostly extending beyond rosettes; peduncle to 0.3 m.

Flowering spring--early summer. Hills, mesas, flats in Sonoran Desert, desert grasslands, oak woodlands, 500--2000 m; Ariz., N.Mex.; Mexico (Sonora).