Phylogeny, karyotype evolution and taxonomy of Cerinthe L. (Boraginaceae).

A phylogenetic and karyological analysis of the small and poorly known genus Cerinthe L. (Boraginaceae-Lithospermeae) was performed using ITS sequences and standard chromosomal techniques. All taxa are diploid with 2n = 16 or 2n = 18 and show a variable degree of infraspecific variation, in particular in the polymorphic C. major and C. minor. Change in base number is associated with an early split between the two well-supported clades of C. major, corresponding to Cerinthe sect. Cerinthe, and that of all other taxa belonging to C. sect. Ceranthe, with the base x = 8 found only in the strictly annual C. major group, and x = 9 in the other five species of the genus: C. minor, C. glabra, C. tenuiflora, C. retorta and C. palaestina. The latter section is subdivided into the E Mediterranean, annual lineage of C. palaestina-C. retorta and the mainly continental, perennial group of C. minor-C. glabra, the sister of which is the Corsican endemic C. tenuiflora. The hypothesis that x = 9 represents the primary haploid number and x = 8 is derived through descending aneuploidy, is discussed. A taxonomic revision of the genus is provided and the following formal taxonomic changes are proposed: C. major L. subsp. oranensis (Batt.) Selvi & Cecchi, stat. nov.; C. major L. subsp. purpurascens (Boiss.) Selvi & Cecchi, stat. nov.; C. minor L. subsp. cleiostoma (Boiss. & Sprun.) Selvi & Cecchi, stat. nov. Cerinthe tenuiflora, C. retorta and the poorly known C. palaestina are well-defined species with little internal variation.