6. Mauritanica clade (BIPP 1).

— In our sampling this clade contains a single species, Thesium mauritanicum (Fig. 3D), from North Africa (Morocco, Algeria). Its position on the phylogenetic tree (Fig. 2A) indicates that it is phylogenetically distinct from the African clade (26). When Battandier (1889) described T. mauritanicum he suggested a relationship with T. bergeri Zucc. (and its synonym T. graecum Boiss. & Spruner) from W Asia and Greece. However, ITS and chloroplast sequences show that species as part of clade 9. The flowers of T. mauritanicum differ little from Eurasian Thesium species but dense pubescence on the stems, leaves, bracts, abaxial surface of the petals and fruits are uncommon characters in the genus. This clade corresponds to T. ser. Mauritanica Hendrych that also included the Libyan endemic T. erythronicum Pamp. It shares with T. mauritanicum a subshrub habit and reticulate fruits; however, the two species differ in several vegetative and inflorescence features suggesting that it might be related to other Paleoboreal species, possibly in clades 8 or 9.