Trillium

"T. grandiflorum is a perennial that grows from a short rhizome and produces a single, showy white flower atop a whorl of three leaves. These leaves are ovate (i.e., egg-shaped) in outline with pointed tips. They lack petioles (or have extremely short ones) and measure 12–20 cm long by 8–15 cm wide (5-8 in long by 3–6 in width), with very prominently engraved venation. The leaves and the stem share a dark green color and persist into autumn. Leaves and petals both have somewhat undulate margins, the leaves often much more strongly so. Individuals grow to between about 15 and 30 cm tall (6–12 inches). A single rootstock will often form clonal colonies, which can become very large and dense."
--From Wikipedia--