Astrophytum — 9 species

Astrophytum is a small genus of slow-growing globular cacti native to Mexico and Texas — including Star Cactus, Bishop's Cap, and specialty cultivars such as Onzuka Bishop's Cap and Astrophytum coahuilense — prized for their ribbed, often white-flecked bodies and cheerful yellow blooms. They demand bright direct or intense indirect light and extremely well-draining soil; use the soak-and-dry method, allowing the growing medium to dry out fully between waterings to prevent root rot. According to ASPCA, Astrophytum species are non-toxic to cats and dogs, making them one of the safer cactus choices for pet households.