Carex species are widespread and abundant components of many regional species pools, where they show various patterns of co-occurrence. They are ecologically different for still largely unknown reasons. Early anatomical studies of the genus already showed considerable variability in root traits; these were, however, not yet assessed systematically. In this study the roots of 107 species of a regional species pool (Germany) were studied with respect to their anatomical and phylogenetic divergence. Traits studied were the root and endodermis (stele) radius, width of the aerenchyma, thickness of the sclerenchyma and the diameter of the largest vessel. Distances of the species were calculated using pairwise Mahalanobis distances, for phylogenetic distances the patristic distance and the numbers of intermittent nodes were used. Many species were anatomically not significantly different albeit visually rather clearly sorted according to morphology. A number of species were, however, significantly deviating from the others. Closely related species may be very similar but also strongly divergent in terms of root traits; phylogenetically more distantly related species were not necessarily anatomically more distant. Only for subgenus Carex, anatomical distance was significantly related to the phylogenetic distance. Species of various clades show, at least for the regional species pool, partly rather unequal divergences. Root structures of Carex show gradual overlapping expressions that may be responsible for slightly different ecological preferences, and may have evolved with different paces and probably a high degree of homoplasy.