of 35 species so far. Globally, the genus, which is of Family Rosaceae, comprises about 1000 species. In Europe, they are more than 300.
The interspecies hybridization and facultative apomixis (asexual seed development) have caused the high morphological variability of the species. That has troubled botanists for ages when relating a specimen to known species and has brought about more and more new species. As a result, new habitats and localities are described for known species which have been considered endemic in some regions before.