Phylogeny and systematics of Lithodora (Boraginaceae—Lithospermeae) and its affinities to the monotypic genera Mairetis, Halacsya and Paramolikia based on ITS1 and IrnLUAA-sequence data and morphology.

Lithodora (Boraginaceae tribe Lithospermeae) comprises nine species of often narrowly endemic dwarf shrubs and shrubs. The genus shows a Mediterranean distribution with the centre of diversity in the western Mediterranean region. Lithodora is distinguished from its allies in Lithospermeae by a shrubby habit, the absence of both faucal scales and an annulus, and a very unusual mericarpid morphology, and it has therefore been regarded as a natural group in the past. Phylogenetic relationships of Lithodora were investigated with nuclear ribosomal ITSI and chloroplast trnLUAA intron sequences using parsimony and likelihood analyses. The results strongly indicate a polyphyly of Lithodora, which falls into two clades: The majority of species forms a monophyletic group ("Lithodora II") in a well supported dade together with a Lit hospermum s.l. dade (including the New World genera Onosmodium and Macromeria) and our sample of Bug!ossoides species. A smaller number of species ("Lithodora I") falls into a second well supported dade including the monotypic genera Mairetis, Paramolikia and Halacsya. A critical reevaluation ofcarpological characters traditionally used to delimit Lithodora corroborates the results of the molecular analysis and indicates that the cupulate areole and the mericarpid appendage found in the genus are homoplasious. The polyphyly of Lithodora is formally recognised by removing "Lithodora II" as a newly established genus, Glandora. The seven newly required combinations in the genus are provided. [ABSTRACT FROM AUTHOR]