Plant Ecology and Evolution 149(1): 45-58, doi: 10.5091/plecevo.2016.1128
Microsatellite analysis of four similar Euphrasia (Orobanchaceae) species changes the traditional view of this group
expand article infoŠárka Svobodová, Jiří Košnar, Petr Koutecký, Milan Štech
Open Access
Background and aims – The genus Euphrasia comprises a taxonomically intricate group. In Central Europe, E. nemorosa and E. stricta are widely accepted species. However, the occurrence of putative intermediate morphotypes considered to be the result of regular hybridization makes identification of populations often difficult. Besides these mostly late-flowering species, two mostly early-flowering species, E. coerulea and E. slovaca, are distinguished in the Sudeten and in the Carpathians, respectively. Because of the doubtful nature of intermediate forms and difficult distinction of early-flowering morphotypes, the aims of this study were to find genetically supported groups and test morphological differences among them.
Methods and key results – We conducted a survey of the genetical and morphological diversity in 42 populations, which were assigned to four species based on morphology. Using microsatellite analysis, we discovered three genetic groups within our data set. Whereas E. stricta and E. nemorosa comprised separate clusters, most of the early-flowering populations identified as E. coerulea and E. slovaca formed one common cluster. Traditional characters such as corolla length, branching and the presence of a long awn on the bracts were identified in multivariate analyses as the most reliable morphological differences between genetically defined E. stricta and E. nemorosa. Early-flowering populations differed generally by their low number of nodes. In spite of their genetic similarity, they differed morphologically between the two geographical areas. In spite of the assumption of different selfing rates correlated with corolla size, differences in genetic diversity among populations with different corolla sizes were not found.
Conclusions – There are three well supported groups in the studied dataset of Euphrasia species. Delimitation of E. stricta and E. nemorosa is in concert with traditional views, but delimitation of the third group changes the traditional distinction of two mostly early-flowering species in the study area.