Stems slender, erect, simple or sometimes branched, more or less hairy or nearly smooth, 6 to 25 inches high, from a perennial root which propagates by suckers. Leaves opposite, oblong to oblong-lanceolate, acute at the apex, or the lower ones blunt, sharply toothed, narrowed at the base into short, slender petioles, smooth or sparingly pubescent, 1 to 3 inches long, one-half to 1 inch wide, and when crushed giving off the odor of Pennyroyal. Whorls of flowers all axillary, often shorter than the petioles. Calyx oblong-campanulate, hairy all over, five-nerved, with five acute, short teeth. Corolla white or slightly pink, about one-eighth of an inch broad, four-lobed, the posterior lobes broader than the others.
Memoir 15 N. Y. State Museum
A. American Wild Mint - Mentha canadensis