Trillium sessile

Trillium sessile (Toadshade or Sessile Trillium) is a perennial spring wildflower native to the central part of the eastern United States and the Ozarks. It has stalkless flowers with erect petals and erect to spreading sepals.  The petals range from maroon or purple to yellow-green forms. This trillium can get quite large and seems to be immune to the ravages of deer, likely due  to the flowers odor (subtle, unless you put your nose into the flower).  It is also a good self spreader.