This plant is the (missnamed) "Yellow Dog-Tooth Violet" or (better) "Yellow Trout Lily" (Erythronium rostratum). In spite of its name, this is not a violet at all; its a member of the lily family (Liliaceae). Apparently other common names are "adders tongue" and "fawn lily". According to Stanwyn Shetler (Botanist at the Smithsonian), it takes 4-7 years from seed to blooming. These plants grow in extensive clonal colonies; the average age of a colony (in one study) was 150 years and the oldest was 1,300 years!!!! The yellow flowers track the sun and close at night. (source: Virginia Native Plant Society)
