Floral trait variation in four Cyclamen (Primulaceae) species

The purpose of this study is to examine floral trait variation between four Cyclamen species that show variation in their ability to reproduce in the absence of pollinators and in levels of inbreeding. Pollen and ovule production, pollen/ovule ratio, pollen volume, petal length and width, diameter of the corolla mouth, pistil and stamen length, and stigma-anther separation varied significantly between the four study species. Flower, pollen and ovule production, pollen volume and corolla size were generally highest in C. hederifolium, the species with the lowest level of inbreeding (mean F-is = 0.329), intermediate in both species with relatively high levels of pollinator-mediated inbreeding, C. repandum (mean F-is=0.658) and C. creticum (mean F-is=0.748), and lowest in the highly inbred C. balearicum (mean F-is = 0.930). The two species with the most different inbreeding coefficients, C. hederifolium and C. balearicum, had lower pollen-ovule ratios and shorter longevities of stigma receptivity and pollen viability than C. creticum and C. repandum. These patterns of variation in floral traits are discussed in relation to the relatedness, pollination ecology and levels of inbreeding of the four species.