Trillium vaseyi Harbison
Trillium erectum L. var. vaseyi (Harbison) H.E. Ahles
Vasey’s trillium is native to the southeastern United States.
Identification: Plants have one to two round stems, and are 12-26" (30-65 cm) tall. Three leaves form a whorl atop each stem. Leaves are almost triangular in shape, sometimes wider near the base than they are long, 4-8" (10-20 cm) × 2-8" (6-20 cm) in size. While the flower appears above the leaves in many species of Trillium, these droop below, on a short petiole. Each flower is maroon (rarely yellow) in color, with three petals, 1-2½" (3-6.5 cm) × 1½-2" (4-6 cm). Each flower has a mild sweet odor. Fruits are dark reddish maroon, generally oval but sometimes with flattened sides, ⅜-½" (1-1.4 cm) × ⅜-¾" (1-2 cm).
See also this Trillium comparison table.
Trillium vaseyi at the Lady Bird Johnson Wildflower Center
Trillium vaseyi on Wildflowers of the United States
Trillium vaseyi at the New England Wild Flower Society
Trillium vaseyi on eFloras
Trillium vaseyi description by Thomas H. Kent, last updated 12 Oct 2018.