Perennial or annual herbs, strongly aromatic of peppermint. Leaves simple, entire, ovate to oblong, nerves ± prominent beneath. Verticillasters many-flowered, forming capitate or elongated spike-like inflorescences. Flowers often male-sterile. Calyx narrow tubular, villous in throat, slightly bilabiate, teeth short, ± connivent in fruit. Corolla white, rose or purple; tube little exserted beyond teeth; upper lip straight, subentire; lower lip 3-lobed. Stamens 2, included under upper lip or subexserted; anther margins often cohering, thecae unilocular by fusion or 2-locular with a fertile theca and a separated reduced lower theca, fertile or not Staminodes present. Style 2-lobed of markedly dissimilar lengths. Nutlets ovoid, smooth, brown, not trigonous.
A mainly SW Asiatic genus extending to E Europe and, eastwards, to the Himalayas and the Altai mountains. The annual species are fairly distinct, taxonomically; in contrast, the perennials are the reverse and in need of a major overall re-assessment.
