Fig. 5.
Axes 1 and 2 of the two-dimensional non-metric multidimensional scaling ordinations of populations based on their pairwise genetic distances. The final stress value for the two-dimensional configuration was 0·08. Vectors fitted represent the substrate classes dominating the Stauracanthus populations: Miocene and Pliocene substrates (r2 = 0·51, P< 0·01) and older and coarse-textured sedimentary substrates (r2 = 0·66, P< 0·001). Triangles, S. boivinii; squares, S. genistoides and S. spectabilis; dark colours, Moroccan populations; pale colours, Iberian populations.