4. Mentha longifolia (Linnaeus) Hudson, Fl. Angl. 221. 1762.
欧薄荷 ou bo he
Mentha spicata Linnaeus var. longifolia Linnaeus, Sp. Pl. 2: 576. 1753; M. sylvestris Linnaeus, 1763.
Plants rhizomatous, perennial. Stems erect, to 1 m, much branched, whitish, striate, retrorse short tomentose-villous. Leaf blade ovate to oblong-lanceolate, to 6 × 1.5 cm, appressed tomentose-villous, subglabrescent, base rounded to shallow cordate, margin coarsely irregular serrate-dentate, apex acute. Verticillasters in cylindric terminal spikes 3-8 cm, lower ones somewhat lax; floral leaves linear-subulate, mostly shorter than verticillasters. Pedicel to 2 mm. Calyx campanulate, ca. 2 mm, tomentose-villous, obscurely 5-veined; teeth linear-subulate, ca. 1 mm, close together in fruit. Corolla purplish, ca. 4 mm, sparsely puberulent; tube ca. 2 mm, gradually dilated upward; lobes oblong, obtuse; upper lobe oblong-ovate, emarginate. Ovary glabrous. Fl. Jul-Sep.
Nanjing Shi, Shanghai Shi, and other cities [Russia; SW Asia, Europe]
Cultivated in China. A polymorphic aromatic herb used medicinally.
Mentha asiatica, M. vagans, and the Himalayan M. royleana Bentham all are very closely related to and perhaps doubtfully distinct from M. longifolia. Further work is needed to fully assess their correct status.