A. thaliana flowering and climatic variation in the south-western Mediterranean region. A) Flowering time and B) leaf number of Moroccan and Iberian accessions. C) Obligate vernalization requirement, D) flowering time (left column) and leaf number (right column), and E) mean temperature (left column) and precipitation (right column) of the driest quarter, in the four genetic groups detected with STRUCTURE in the Iberian Peninsula and in Morocco. In C-E, bars are the mean ± SE of the accessions assigned to each genetic group, except that group 3 is divided in Iberia (IP-3) and Morocco. Shared or different letters above bars indicate non-significant and significant differences between groups (P < 0.05) according to Tukey tests. Bar colors are similar to group colors shown in Figure 2.