The genus Galanthus
Biologist classify all living things so that those most closely related are named and situated together. Thus the genus Galanthus contains a group of different kinds of plants which are believed to be more closely related to each other than they are to other kinds of plants.
In the case of snowdrops there is little doubt that they have got it right. Even the untrained eye can recognise a snowdrop and although the different species have differing characteristics they are all obviously snowdrops first and foremost.