Butter and Eggs (linaria vulgaris), aka common or yellow toadflax, is a member of the plantain family and is similar in looks to the snapdragon. It is an introduced species in North America, and in Colorado, Butter and Eggs is deemed a noxious weed in need of eradication, as it tends to crowd out native flora.
The petals of Butter and Eggs flowers are rather “tight-lipped” and it takes a strong, determined bee to get at the pollen inside.
The Butter and Eggs plant has been used extensively in folk medicine. Among other uses, it can serve as a laxative and diuretic and the flowers can be used to prepare an ointment to treat various skin conditions.