The genus with ball-shaped cacti from both mountainous and lowland areas of South America. Most of them listed under Lobivia, although they usually need more water and less light than Lobivia itself. They are easy to cultivate as can be watered a lot, fertilized a lot and kept even on the windowsill and flower! there. Some flower at night with huge white flowers, other, especially very numerous hybrids, flower during the day and the flowers are of all imaginable colours except for blue.