Dudleya, commonly known as liveforevers (Spanish: siemprevivas) is a genus of rosette-forming succulent plants in the stonecrop family, Crassulaceae, consisting of about 68 taxa in southwestern North America and Guadalupe Island. The species come in many forms, with some large and evergreen, others geophytic and deciduous, but despite their dramatic variations in appearance, most species readily hybridize. The flowers of Dudleya have parts numbered in 5, with the petals arranged in tubular, star-shaped, and bell-shaped forms, and when fruiting are filled with tiny, ovoid to crescent-shaped seeds. The genus evolved as neoendemics, from ancestors in the stonecrop genus, Sedum. The ancestors radiated southward from Sedum during the creation of the dry summer climate in the California region 5 million years ago. Early botanists classified the larger species as Echeveria and Cotyledon, while the geophytic species were placed as Sedum. Taxonomic efforts started by Joseph Nelson Rose and Nathaniel Lord Britton created three genera, which were all eventually subsumed into the Dudleya proper following Reid Moran's investigations into the genus. Phylogenetic research is still at an early stage in the genus, and is complicated by the fact that many species are becoming endangered. Dudleya is a relatively obscure genus in comparison to other more widely-cultivated succulents, but converging interests by succulent collectors, native plant enthusiasts and gardeners have led to cultivation of many species as ornamental plants. In the wild, many species of Dudleya are vulnerable, as land development and poachers threaten often niche populations of plants. Poached plants are often shipped to East Asia, especially South Korea. Conservationists, nurseries and governments combat Dudleya poaching through propagation programs and protection laws. Description Characteristics and subgenera This genus is the only taxon of the Sedeae tribe to have evolved sympodial branching. The genus is traditionally divided into three subgenera, two of which were formerly their own genera. The subgenera consist of Dudleya, Stylophyllum, and Hasseanthus. Epicuticular wax One of the most famous features of some Dudleya are their waxy coating. Numerous species have their foliage covered in an epicuticular wax, or farina. This waxy coating is usually white, chalky, and mealy, and is the namesake in many epithets, like chalk dudleya, powdery liveforever, and giant chalk dudleya. The wax on the giant chalk dudleya is a surface with some of the highest ultraviolet reflectivity ever discovered in plants. When exposed to water, the wax may coat drops on leaves, preventing their evaporation.