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The tribe Genisteae includes genera of great ecological importance in Mediterranean countries because they are dominant elements of many plant communities. Genetic variation and diversification patterns in Stauracanthus (Genisteae) provide information relevant for the study of the processes of diversification in relation to the environmental history of the western Mediterranean. Nineteen populations of S. boivinii and S. genistoides were assessed by 11 chloroplast microsatellite markers, revealing 44 haplotypes. Both species had different haplotypes and contrasting patterns of karyological, morphological, and genetic variation. In the minimum spanning tree of the haplotypes, AMOVA analysis, and nested clade analysis, S. boivinii had high levels of differentiation and restricted gene flow among populations. Allopatric differentiation occurred between the Moroccan and Iberian populations of S. genistoides, although S. genistoides subsp. spectabilis and subsp. vicentinus had high levels of differentiation among populations (F(ST)), whereas S. genistoides subsp. genistoides had a low F(ST). Genetic patterns are discussed in relation to the Messinian salinity crisis (MSC): hard conditions drove plants to refuge habitats along the Atlantic coast and higher altitude areas in the Moroccan mountains (S. genistoides subsp. spectabilis and S. boivinii). After the MSC, S. boivinii underwent polyploidization and expansion, whereas S. genistoides expanded and continued diversifying into S. genistoides subspp. genistoides and vicentinus.

Genetic variation in 27 populations of Ulex species from southern Spain and northern Morocco (Betic-Rif arc) was assessed using 11 chloroplast microsatellite (cpSSR) markers, which revealed 47 different haplotypes. These nonrecombinant, haploid markers allow measurement of genetic variation in closely related species of Ulex where molecular phylogenetic analyses have not provided a clear view of interspecific relationships. Discriminant analysis indicates that the haplotypes are useful to differentiate among species, and analysis of molecular variance (AMOVA) shows high levels of differentiation among populations. The minimum spanning tree (MST), that represents the connections between the haplotypes, suggests that the eastern Rifean U. africanus haplotypes are more genetically related than those from southern Spain. The latter may have lost genetic diversity while colonizing new habitats, eventually differentiating into U. baeticus and U. scaber. Hybridization between these populations, followed by polyploidization, may have originated the tetraploids (U. congestus and U. borgiae) that colonized new habitats associated with acidic rocks. Separate groupings of U. scaber populations may indicate multiple origins from different stocks. Diversification in this group of Ulex species could be related to the opening of the Alboran Sea by Middle Miocene, when the populations from Morocco and Spain became isolated from each other.