Erythronium americanum (common names: Adder Leaf)

Trout lily is a native perennial found in dry deciduous woods. Also called Dogtooth Violet, Adder's Tongue, Fawn Lily, Yellow Trout Lily is a member of the Lily family, not a violet ("Dogtooth" refers to the tooth shape of its underground bulb-like corm.) The common name "Trout" comes from its mottled leaves which resemble the coloring of a Brown Trout. This wildflower reproduces mostly by underground bulb-like corms often forming huge colonies. It may take up to seven years for a plant to be mature enough to flower. This flower is nearly identical to White Trout Lily except for the color. Never attempt to dig this flower from the wild as its corms are very deep with a thin, fragile stem.
The leaves are edible to deer and also to human, and the roots as well as the leaves have many medicinal uses. WARNING: the use of the leaves may cause an allergic reaction.

I'm lucky to live near a large hillside covered with Trout Lily, and it's also in our back woods and in my yard.