[Wikipedia] Monotypic Genus, Etymology,: Pseudotrillium is a monotypic genus of flowering plant in the family Melanthiaceae. Its sole species, Pseudotrillium rivale, is commonly known as the brook wakerobin.[5] It is endemic to the Siskiyou Mountains of southern Oregon and northern California. The Latin specific epithet rivale means “growing by streams”, with reference to a preferred habitat.[6] (link added by Mary Ann Machi)