Gymnocalycium — 22 species

Gymnocalycium, commonly called Chin Cacti, is a genus of small, ribbed South American cacti that stand out for their ability to thrive in lower light than most cacti — bright indirect light suits them well, with some direct morning sun appreciated. Water deeply but infrequently, letting the soil dry completely between waterings, as they are highly susceptible to rot in wet conditions. The well-known Moon Cactus is a grafted Gymnocalycium. According to the ASPCA, Gymnocalycium cacti are non-toxic to cats and dogs, though their spines pose a physical hazard.