Annual, 5-15 (-30) cm, simple stemmed or branched from the base, aromatic (peppermint). Stems leafy with a ± dense indumentum of short retrorse eglandular hairs, green or purplish. Leaves lanceolate, linear lanceolate to ± linear, 7-25 x 2-6 mm, narrowed above and below, scabridulous, margins ± ciliate, prominently, veined below, sparingly gland-dotted or not; petiole absent to 2 mm. Inflorescence a dense oblong, elongated or short, spike. Verticillasters 6-8-flowered, sometimes present from base of stem upwards; leaves or floral leaves ciliate, much exceeding flowers. Calyx narrow tubular, 6-8 mm long with short and long spreading eglandular hairs and sessile oil globules, scarcely bilabiate; teeth very short, triangular-oblong, connivent. Corolla lavender, pink or lilac, 8-10 mm; tube slender scarcely cxserted beyond calyx teeth. Anthers glabrous; lower thecae ± sterile, appendage-like. Nutlets c. 1.5 x 0.75 mm, oblong trigonous, rounded apically, pale brownish, finely granulate.