Parodia werneri f. inermis is the nice spineless form of Parodia werneri (syn: Notocactus uebelmannianus). The spines are present but extremely reduced only about 1 mm long and completely disappear in the wool of areoles, all the other characteristics namely size and shape of stems, flowers, fruits, roots etc. clearly show that they are conspecific. It's easy to grow and quite resistant to neglect. Nevertheless, it is appropriate to provide adequate growing conditions in order to obtain abundant blooms.