The name of the genus Gymnocalycium comes from two acient greek word: ‘gymnos’ means ‘naked’, and ‘calyx’ is called ‘cup’ in English, referring to the spine-free flower tube of this plants. The genus was first described by the German medical doctor and cactus expert Pfeiffer in 1843. Plants belonging to this genus bear various form, size, spines and flowers, nevertheless most of them are flattened-globular and only a few form short columns in their old age. Based on seed morphology, five sections are able to separate within the genus, as follows: Macrosemineum, Gymnocalycium, Microsemineum, Trichomosemineum, Muscosemineum.
