Since the Trilliaceae or the Trillium family was recognized in 1846 by Lindley there have been many changes in its placement and in the genera included in it. It has been part of Liliaceae, but is no longer. The APG II system (2003) moves the genera in this family into the Melanthiaceae family. These two families have separate morphological characteristics however and some still consider Trilliaceae a separate family. The four or five genera are mostly woodland plants with whorled leaves and flowers. Distribution ranges from North America to Eurasia. They are rhizomatous or rhizomatous and tuberous with solitary and terminal flowers. The perianth has a distinct calyx and corolla and the ovary is superior and multi-chambered. Perianth parts are in 3s, from 6 to 8 and are not joined. The fruit is a capsule or a berry.