Résumé
A striking feature of the Mediterranean flora concerns the high rates of narrow endemism within many regions. The prevailing paradigm for the evolution of such endemism relies on an important role of geographic isolation and allopatric speciation. Until recently there has been little work on the precise ecological differences among endemic plants and their congeners in the Mediterranean region and the potential role of ecological specialisation in isolation and speciation. This paper has two objectives. First, we evaluate general ecological differences among endemic and widespread congeners in the flora of the western Mediterranean. The results and review of the literature attest to consistent patterns of ecological differentiation among endemic species and their snore widespread congeners. Second, we present results of a detailed study of morphological, molecular and ecological differentiation in a group of spring-flowering Mediterranean Cyclamen species. This study illustrates how differentiation in geographically peripheral and ecologically marginal populations may contribute to the diversification of endemic species whose contemporary distributions are disjunct from con-generic species.