Stems smooth, four-angled, erect, 1 to 3 feet high from a perennial root. Leaves opposite, oblong to lanceolate in shape, with serrate margins, acute at the apex, sessile or auricled-clasping at the base, 2 to 4 inches long, one-half to 1 inch wide. Flowers violet-purple, borne solitary in the axils of the upper leaves on long, slender stalks. In fruit these stalks become 1 to 2 inches long and two to four times as long as the calyx. The calyx is prismatic, five-angled, with five slender, pointed teeth. Corolla about 1 inch long, consisting of a cylindrical tube which is longer than the calyx, and an upper and a lower lip; upper lip two-lobed and reflexed, lower lip three-lobed and spreading, the throat of the flower closed by a prominent yellow palate. The plant derives its name from the fancied resemblance of the flower to a grinning face.
Memoir 15 N. Y. State Museum
B. Square-Stemmed Monkey Flower - Mimulits ringens