trillium

Any of a group of perennial herbaceous woodland plants belonging to the lily family, native to Asia and North America. They have a circle, or whorl, of three leaves around the stem, at the end of which the single flower has three green sepals and three usually maroon or white petals. The nodding trillium T. cernuum ranges across most of the eastern half of North America. (Genus Trillium, family Liliaceae.)