Linaria markotchensis (Plantaginaceae), а new species from the Western Caucasus

Abstract

Linaria markotchensis (Plantaginaceae), а new species from the Western Caucasus, is described, illustrated and compared with its morphologically closest relatives from L. sect. Linaria (L. altaica, L. biebersteinii, L. macroura, L. odora and L. vulgaris). The new species is different from L. subsect. Laeves (L. altaica, L. macroura, L. odora) by the surface disk of the seed being covered with tubercles and short ridges and therefore should be assigned to L. subsect. Tuberculatae, in which it is distinguished by its habit. The main characters of L. markotchensis are the small size of the shoots; densely arranged alternate leaves, their number and succulence; lack of pubescence, except for some rare, very small glandular trichomes on the inner side of the sepals and corolla; black, shiny, reniform to orbicular-reniform seeds, with a wide black leathery wing; surface disk of the seed covered with tubercles and short ridges. Linaria markotchensis is a narrowly endemic species, growing on marl scree slopes of the Markotkh Ridge, Western Caucasus (Russia, Krasnodar Territory).