Both S. bonplandiana, and S. taxifolia have identical ranges; both species range from the Trans-Mexican Volcanic Belt southward, on an imaginary centerline into central Guatemala. Each is on the Pacific Coast, but leave the coastal strip before the range extension into central Guatemala. Both have their disjunct ranges in Arizona, both being in the Madrean Sky Islands region. Both also range into Baja California Sur, but S. taxifolia only at the extreme south. (S. bonplandiana also occurs in Arizona, in the Mogollon Rim-White Mountains regions.)