Erythronium, the fawn lily, trout lily, dog's-tooth violet or adder's tongue, is a genus of Eurasian and North American plants in the lily family, most closely related to tulips. The name Erythronium derives from Ancient Greek ἐρυθρός (eruthrós) "red" in Greek, referring to the red flowers of E. dens-canis. Of all the established species, most live in North America; only six species are found in Europe and Asia.

The Lilioideae are a subfamily of monocotyledonous perennial, herbaceous mainly bulbous flowering plants in the lily family, Liliaceae. They are found predominantly in the temperate and colder regions of the Northern Hemisphere, particularly East Asia and North America. The subfamily includes two tribes. They are of economic importance, particularly the lilies and tulips.