Mentha longifolia, (L.) Hudson

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 186

12. M. longifolia (L.) Hudson , FI. Angl. 221 (1762)

( M. sylvestris L. , M. incana Willd. ).

Perennial 40-120 cm, with a musty scent. Stem white- or grey-villous, sometimes sparsely hairy. Leaves (40-)50-90(-110) x (10-)20-40 mm, sessile or very shortly petiolate, smooth or slightly rugose near the base, usually oblong-elliptical, acute, serrate with usually irregular, patent teeth, green to grey-tomentose above, grey- or white-villous beneath; hairs simple, with the basal cell 18-33 p m in diameter. Verticillasters many, usually congested, forming a terminal, usually branched spike 40-100 x (9-) 10-15 mm. Calyx (1-) 1-5-3 mm, narrowly campanulate, hairy; teeth subequal. Pedicels hairy. Corolla lilac or white. Fertile anthers 0-28-0-38 mm. Nutlets 0-54-0-79 mm. 2/? = 24. M ost o f Europe, from S. Sweden and N. C. Russia southwards. Al Au Be Bu Cr Cz Ga Ge G r He Hs Hu It Ju Lu Po Rm Rs (B, C, W, K, E) Si Su Tu. Extremely variable in height, leaf-size and -shape, indumentum and inflorescence, and complicated by the occurrence of hybrids. There is clinal variation from west to east with reduction in size of leaves and calyx. Plants from Austria and eastwards with narrow leaves, narrow interrupted spikes and smaller calyx have been described as M. longifolia subsp. grisella (Briq.) Briq. in Engler & Prantl, Natiirl. Pflanzenfam. 4(3a): 322 (1897). These, however, grade imperceptibly into 13, with which there appears to have been very extensive hybridization. As a result, many populations, especially from Hungary, and to a lesser extent from the Balkan peninsula and S. Italy, are extremely complex. The distribution in W. Europe is partly obscured owing to confusion with hairy plants of 14, to which all records of 12 from N.W. Europe appear to be referable.