Mimulus subg. Schizoplacus is one of two subgenera in the genus and is characterized by parietal placentation, marcescent corollas, and pedicels that are shorter than the calyces. All but three of the thirty species are annuals; two of the three perennial species are herbs and one is a shrub. They are found only in California, U.S.A., and all adjacent states, including Baja California, Mexico, as well as a few places in Washington, Montana, and Wyoming.