Stem. - Square, low, erect, branching, Leaves. - Opposite, aromatic, small. Flowers. - Purplish, small, whorled in the axils of the leaves. Calyx. - Two-lipped, upper lip three-toothed, the lower two-cleft. Corolla. - Two-lipped, upper erect, notched at apex, the lower spreading and three-cleft. Fertile stamens. - Two. Pistil. - One, with a two-lobed style.

This well-known, strong-scented little plant is found throughout the greater part of the country, blossoming in midsummer.

Its taste and odor nearly resemble that of the true pennyroyal, Mentha pulegium, of Europe.