Relazioni filognetiche di Halacsya Doerfl., Paramoltkia Greuter e generi affini (Boraginaceae-Lithospermeae) su base molecolare e morfologica.

Tribe Lithospermeae DC. (Boraginaceae) includes 24 genera and c. 415 species in America, Europe, Asia and Africa. Our present knowledge of this group is mostly based on a series of papers by I.M. Johnston published about a half century ago. In the Euro-Mediterranean region it is represented by 16-18 genera, but uncertainties still exist on the relationships and even circumscription of some genera, e.g. Lithospermum s.l., Moltkia, Arnebia, Macrotomia, Podonosma and others. As in other Boraginaceae groups, this is due to the difficult interpretation of shared characters as phylogenetically informative homologies or as simple analogies. Here we present the results of the first study on the phylogeny of circummediterranean Lithospermeae, based on ITS and matK DNA sequences obtained from members of 18 genera. Using members of Echiochileae as outgroup, we confirm the monophyly of the group and suggest some relationships which were not hypothesized before, especially concerning the Balkan monotypic genera Halacsya and Paramoltkia, both obligate serpentinophytes. Mapping the aptitude of the taxa to grow on ultramaphic soils, either obligatedly or facultatively, we suggest that serpentinophytism may have originated at least three times in different lineages of Lithospermeae, e.g. the Onosma, the Halacsya-Paramoltkia and the Echium-Pontechium clade.