Variation of seed morphology of Trollius europaeus L. and Trollius altissimus Crantz (Ranunculaceae)

The aim of this study was to investigate seed morphology and intra- and inter-population variation of seeds of Trollius europaeus L. and Trollius altissimus Crantz., two controversial species regarding their taxonomical position. We analyzed seed-coat microsculpture and some biometrical traits (length and width, width/length ratio, volume and projected perimeter). Seed sculpture did not differ between species, but seeds of T. altissimus were usually larger than seeds of T. europaeus. Although species differed significantly in seed morphology, it was possible to show the populations of both species that were similar regarding the analyzed seed traits. We noted a significant inter-population differentiation of seeds in both species with respect to seed-coat microornamentation and biometrical traits. We conclude that T. europaeus and T. altissimus are probably not two distinct species, but T. europaeus should be divided into two lower taxa in the rank of variety or subspecies.