in F. A. Wislizenus, Mem. Tour N. Mexico, 108. 1848.
N.Mex., including n Mexico
Varieties 5 (1 in the flora).
All five varieties occur in northern Mexico (Chihuahua, Coahuila, Durango, Nuevo León, Sonora, and Zacatecas) in oak and conifer woodlands, commonly above 2200 m elevation. In addition to var. atrorubens (including var. psuedociliatum Reveal), they are var. auritulum W. J. Hess & Reveal, var. intonsum Reveal, var. nemorosum W. J. Hess & Reveal, and var. rupestre (S. Stokes) W. J. Hess & Reveal.
"/2" is not declared as a valid unit of measurement for this property.