Intrapopulational polymorphism in Romulea bulbocodium Sebast. & Mauri(Iridaceae)

Even 300 years after Linnaeus, there remains some confusion among botanists about his species concept.A useful approach would be to re-examine his ideas, instead of merely following what botanists after him interpreted from his writings. The family Iridaceae Juss. represents an appropriate case study for this purpose; it is rich in species and doubtful taxa, the latter with polymorphic populations often of supposed hybrid origin. In botanical literature, Romulea bulbocodium is widely described with several subspecies, varietes and forms. However, individuals of wild populations, even from a narrow area, appear to belong to the same species but show high phenotypic polymorphism in flower size and colour and in style/stamen relative lenght. Reported chromosome numbers are 2n=28, 34, 36, 42. With the aim of clarifyng this critical taxon, we previously investigated its morphometric characters. here, we present a molecular analysis of some R. bulbocodium populations using AFLP markers. Despite high morphological variability, individuals cluster together in a single group that is well separated from the related species R. ramiflora. These results suggest that the high morphologiacal polymorphism within R. bulbocodium does not mirror any taxonomic divergence, and help us to interpret Linnaeus species concept.