Crassulaceae

Crassulaceae, the stonecrop family, is a diverse group of flowering plants comprising about 34 genera and around 1,400 species. Members are predominantly succulent plants, including herbs, shrubs, and small trees, adapted to dry environments.

Morphology and physiology: Most species have thick, fleshy leaves that store water, and growth forms ranging from compact rosettes to trailing or upright shrubs. Many Crassulaceae use Crassulacean acid metabolism (CAM) photosynthesis, which improves water-use efficiency under arid conditions. Flowers are typically small and arranged in clusters, usually with five-parted perianth parts, and fruits are generally dry capsules with seeds that vary in size and appearance. Some genera, such as Kalanchoe, produce distinctive plantlets along the leaf margins.

Distribution and ecology: Crassulaceae have a nearly global distribution, with centers of diversity in arid and alpine regions of Africa, Madagascar, the Americas, and Eurasia. They commonly inhabit rocky outcrops, thin soils, and other environments where water is scarce, and they are frequently cultivated in gardens and containers for their drought tolerance and varied foliage.

Horticulture and notable genera: The family is widely grown as ornamentals. Prominent genera include Crassula (jade plants), Sedum (stonecrops), Echeveria, Kalanchoe, and Sempervivum (hens and chicks). Kalanchoe species are noted for leaf-margin plantlets in some varieties. Propagation is commonly by leaf or stem cuttings, offsets, or seeds, with many species forming visually striking rosettes or succulents in cultivation.

Taxonomy: Crassulaceae belongs to the order Saxifragales within the eudicots. The group is recognized for its succulent habit and CAM photosynthesis, contributing to its popularity in horticulture and its ecological versatility.