Flower colour polymorphism (FCP) is the occurrence of at least two discrete flower colour variants in the same population. Despite a vast body of research concerning the maintenance and evolutionary consequences ofFCP, only recently has the spatial variation in morph frequencies among populations been explored. Here we summarise the biochemical and genetic basis ofFCP, the factors that have been proposed to explain their maintenance, and the importance ofFCPand its geographic variation in the speciation process. We also review the incidence ofFCPin the environmentally heterogeneous Mediterranean Basin. Nearly 88% of MediterraneanFCPspecies showed anthocyanin‐based polymorphisms. Concerning the evolutionary mechanisms that contribute to maintainFCP, selection by pollinators is suggested in some species, but in others, selection by non‐pollinator agents, genetic drift or gene flow are also found; in some cases different processes interact in the maintenance ofFCP. We emphasise the role of both autonomous selfing and clonal reproduction inFCPmaintenance. Mediterranean polymorphic species show mainly monomorphic populations with only a few polymorphic ones, which generate clinal or mosaic patterns of variation inFCP. No cases of species with only polymorphic populations were found. We posit that different evolutionary processes maintaining polymorphism the Mediterranean Basin will result in a continuum of geographic patterns in morph compositions and relative frequencies ofFCPspecies.

Species of the genus Iris (Iridaceae) have a long history of traditional medicinal use in many places of the world, and they have been previously recognized as rich sources of secondary metabolites, in which flavonoids are found predominantly. During the last decade (1999-2008) over 90 flavonoid constituents have been discovered and characterized, including 38 new compounds, from 15 species of Iris. This review elucidates the structural features of these flavonoid constituents, and gives the details of their source, identification, biological activity and chemotaxonomy significance. At last, a checklist of the flavonoid compounds in Iris by species is given.

Background and Aims Flower colour polymorphism in plants has been used as a classic model for understanding the importance of neutral processes vs. natural selection in population differentiation. However, current explanations for the maintenance of flower colour polymorphism mainly rely on balancing selection, while neutral processes have seldom been championed. Iris lutescens (Iridaceae) is a widespread species in the northern Mediterranean basin, which shows a stable and striking purple–yellow flower colour polymorphism. To evaluate the roles of neutral processes in the spatial variation for flower colour in this species, patterns of neutral genetic variation across its distribution range were quantified, and phenotypic differentiation was compared with neutral genetic differentiation.