Crassulaceae, or the orpine family, are a family of dicotyledons. They store water in their succulent leaves. They are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce. The family includes about 1,400 species in 33 genera.
No member of this family is an important crop plant, but many are popular for horticulture; many members have a bizarre intriguing appearance, and are quite hardy, typically needing only minimal care. Familiar species include the Jade plant or "friendship tree", Crassula ovata and "Florists' Kalanchoe", Kalanchoe blossfeldia.
Classification within the family is difficult because many of the species hybridize readily, both in the wild and in cultivation. Some older classifications included Crassulaceae in Rosales, but newer schemes treat them in the order Saxifragales.
Crassulacean acid metabolism (CAM photosynthesis) is named after the family, because the pathway was first discovered in crassulacean plants.