The butter-and-eggs, a native of Europe, was introduced into North America by the early settlers because of its many uses: as an ingredient in colonial skin lotion, as a tea made from its leaves to treat constipation (which they most likely would not have suffered from if they had been totally vegetarian), and its juice, mixed with milk, was used as a fly poison around barns.
 The actual size of the butter-and-eggs flower is about one inch long from the top of the upper lip to the bottom of the closed throat, or about one-thirteenth the size of this full-sized photo.  The flower of the butter-and-eggs is formed by a 2-lipped corolla which is spurred at the base.  The upper lip has two lobes which stand erect.   The lower lip has three lobes with an orange coloured base which close the throat.  
 Butter and Eggs is an invasive species which has spread to more than half the counties in Minnesota. It tends to grow in clumps and spreads tentatively as well as by seed. Its main blooming season is early to mid summer, but it's not unusual to find some patches blooming in late spring or early fall. 
 The butter-and-eggs, at close inspection, seems to have a hairy "tongue" resting on the top of the lower lip.  
 Leaves are up to 2½ inches long and 1/8 to 1/6 inch wide with pointed tips and no leaf stalk. Attachment is alternate, but they can be tightly packed along the stem so may appear opposite or whorled. Leaves are toothless; leaves and stems are hairless

Growing up in rural western New York state I am quite familiar with these non-native plants and wildflowers properly called "Eggs and Butter" (Linaria vulgaris.) We just called them by the vernacular name "Snapdragons."
Commonly seen in fields and usually one of the first weeds to colonize recently disturbed soil such as tilled agricultural land, this ruderal species (first to colonize disturbed soils), the snapdragon is classified as both a weed and a flower. Known regionally under different names, Wild Snapdragons are also called bride-weed, bread and butter, false flax, pennywort, yellow toadflax and over two dozen other titles too numerous to include.