Trilliaceae is a family of petaloid, lilioid monocots. To paraphrase what Steven Elliott wrote of the genus Trillium in 1817, "this family is an interesting one. A whorl of leaves at the summit of a stem, supporting a single flower, it contains and conceals many species." In its most recent treatment (Farmer and Schilling 2002) the family, which exhibits an arcto-tertiary distribution, is comprised of 6 genera. Three exhibit a wide distribution: Paris from Iceland to Japan, Daiswa from eastern Asia, and Trillium from North America and eastern Asia; and three are monotypic, endemic genera: Trillidium, with a tepaloid inflorescence, from the Himalayan Mountains; Kinugasa, with petaloid sepals, from Japan; and the newly described Pseudotrillium, with spotted petals, from the Pacific Northwest.