American germander is a colony-forming perennial with a 4-sided, hairy stem that is rarely branched. Flowers are lavender or pink, in terminal and lateral racemes, densely spaced. The corolla has an unusual configuration; it seems to have no upper lip, since those 2 lobes are pointed upward like horns, while the lower lip is much larger and more complicated, with 2 rounded side lobes and a large, cupped, bottom lobe; 4 stamens protrude noticeably, with reddish-brown anthers. Blooms June–September. Leaves are opposite, lanceolate, sharply pointed; on petioles; with sharp or rounded teeth. Crushed foliage has a slightly foul odor.
Similar species: Two varieties of this species have been recorded for Missouri, and they are difficult to tell apart. American germander has several characteristics in common with its mint-family relatives, such as the square stems, opposite leaves, and two-lipped flowers. But this is the only mint in our state with the unique corolla lobe configuration.