in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. 1859.
Euphorbia pediculifera can be variable in terms of leaf shape and the extent of pubescence, but the species is readily identified by the short, appressed hairs on the leaves and the distinctive seed that is encircled by a series of round, transverse ridges.
Ariz., Calif., nw Mexico.
Varieties 2 (1 in the flora).
Euphorbia pediculifera var. linearifolia S. Watson is found only near Guaymas in southwestern Sonora, Mexico.