Astrophytum is a genus that now includes six North American cacti species found in Mexico and some areas of the U.S. Three of the six species are fairly common in residential cultivation, and they are sometimes known collectively as star cactus—named for the ribbed structure that has a star-like shape when the plant is viewed from above. The body is covered with aureoles from which sharp black or golden spines protrude. Several of the species grow white flocking on the body—an adaptation designed to protect the plant's tissues from the sunlight.

Astrophytum cacti are known for their beautiful growth habit and unusual shape (they are sometimes known as "living rocks") as well as for lovely yellow flowers that extend up from the apex.

Astrophytum species, like most cacti, are generally very slow-growing. Although mature specimens are quite impressive, it can take years to nurture an Astrophytum to that level. These are also very difficult plants to cultivate; they are often grafted onto an Echinopsis cactus for best results. Although not easy plants to nurture, if properly grown, these are among the most beautiful of North America cacti.
 
Size guide:
Mini - 6cm 
Small - 8cm 
Medium - 10cm
Large - 13cm
Extra Large - 15 cm