White Trillium, aka, white wake-robin, wood lily (Trillium grandiflorum)

"Trillium grandiflorum" is a species of flowering plant in the family Melanthiaceae. A monocotyledonous, herbaceous perennial, it is native to eastern North America, from northern Quebec to the southern parts of the United States through the Appalachian Mountains into northernmost Georgia and west to Minnesota.