Most similar to the Compton Tortoiseshell (Roddia l-album = N. vaualbum), but californica has a black dorsal hindwing margin, not heavily marked with orange-brown as in l-album. There are no described subspecies; the name herri mentioned by Bird et al. is a cool-weather induced phenotype according to Guppy & Shepard (2001). There appears to be little geographic variation in this species, possibly due to the fact that it is able to migrate long distances, resulting in mixing of populations.