Plants usually herbs, sometimes subshrubs, treelike, or aquatic, usually succulent. Leaves alternate, opposite, or whorled; stipules not present. inflorescences usually terminal or axillary inflorescences. Flowers radially symmetric, usually bisexual, 3-12 (- about 30)-merous; sepals free or united into a tube; petals as many as the sepals, free or united into a tube; stamens as many as or twice as many as the number of petals, free or attached to the corolla; anthers 2-thecous, introrse; nectaries at the base of the the carpels, usually scalelike; carpels superior, as many as the the petals, free or united at the base; ovules 1-many. Fruits a whorl of follicels, usually opening on the adaxial side; seeds minute, endosperm usually present, embryo straight.
The Crassulaceae includes 34-35 genera and about 1500 species. The species are most abundant in the northern hemisphere and southern Africa, mostly in warm, dry regions. It is rare in the wet tropics.
The species are easy to cultivate from seed or cuttings but cultivated plants may differ a lot in their appearance from wild plants because they are kept more moist. The dimensions in the descriptions are based on dried specimens collected from plants growing in the wild.