Saxifragales is an order of angiosperms, or flowering plants, containing 15 botanical families and around 100 genera, with nearly 2,500 species. Of the 15 families, many are small, with eight of them being monotypic. The largest family is the Crassulaceae (stonecrops), a diverse group of mostly succulent plants, with about 35 genera. Saxifragales are found worldwide, primarily in temperate to subtropical zones, rarely being encountered growing wild in the tropics; however, many species are now cultivated throughout the world as knowledge of plant husbandry has improved. They can be found in a wide variety of environments, from deserts to fully aquatic habitats, with species adapted to alpine, forested or fully-aquatic habitats. Many are epiphytic or lithophytic, growing on exposed cliff faces, on trees or on rocks, and not requiring a highly organic or nutrient-dense substrate to thrive.
The Crassulaceae, also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crassulacean acid metabolism (CAM). Flowers generally have five floral parts. Crassulaceae are usually herbaceous but there are some subshrubs, and relatively few treelike or aquatic plants. Crassulaceae are a medium-sized monophyletic family in the core eudicots, among the order Saxifragales, whose diversity has made infrafamilial classification very difficult. The family includes approximately 1,400 species and 34–35 genera, depending on the circumscription of the genus Sedum, and distributed over three subfamilies. Members of the Crassulaceae are found worldwide, but mostly in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce, although a few are aquatic.
Sedum is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. The genus has been described as containing up to 600 species, subsequently reduced to 400–500. They are leaf succulents found primarily in the Northern Hemisphere, but extending into the southern hemisphere in Africa and South America. The plants vary from annual and creeping herbs to shrubs. The plants have water-storing leaves. The flowers usually have five petals, seldom four or six. There are typically twice as many stamens as petals. Various species formerly classified as Sedum are now in the segregate genera Hylotelephium and Rhodiola.
Disocactus crenatus, commonly known as the crenate orchid cactus, is a species of cactus cultivated for its large flowers. It is a critical parent plant in creating epiphyllum hybrids commonly cultivated worldwide.
Hylotelephium telephium, known as orpine, livelong, frog's-stomach, harping Johnny, life-everlasting, live-forever, midsummer-men, Orphan John, witch's moneybags, and garden stonecrop is a succulent perennial plant of the family Crassulaceae native to Eurasia. The flowers are held in dense heads and can be reddish or yellowish-white. A number of cultivars, often with purplish leaves, are grown in gardens as well as hybrids between this species and the related Hylotelephium spectabile (iceplant), especially the popular 'Herbstfreude'. Occasionally garden plants may escape and naturalise as has happened in parts of North America.
Rhodiola is a genus of perennial plants in the family Crassulaceae that resemble Sedum and other members of the family. Like sedums, Rhodiola species are often called stonecrops. Some authors merge Rhodiola into Sedum.
Phedimus spurius, the Caucasian stonecrop or two-row stonecrop, is a species of flowering plant in the family Crassulaceae. It is still widely listed in the literature as Sedum spurium.
Rosularia is a small genus of the family Crassulaceae. It includes about 28-35 species from Europe, the Himalayas, and northern Africa.
Hylotelephium is a genus of flowering plants in the stonecrop family Crassulaceae. It includes about 33 species distributed in Asia, Europe, and North America.
Aizopsis is a genus of the succulent family Crassulaceae, found in east Asia.
Petrosedum is a genus of the succulent family Crassulaceae.
Phedimus is a genus of the succulent family Crassulaceae, with about 18 species, distributed in eastern Europe and Asia. The genus is described with two subgenera, but one of these is also recognized as a separate genus, Aizopsis. Phedimus kamtschaticus is widely grown as an ornamental ground cover and has gained the Royal Horticultural Society's Award of Garden Merit.
Petrosedum is a genus of the succulent plant family Crassulaceae.
Echeveria runyonii is a species of flowering plant in the family Crassulaceae, that is native to the state of Tamaulipas in Mexico. Several cultivars have been described and cultivated.
Orostachys is a genus of the succulent family Crassulaceae that contains about 15 species. It is a biennial herb growing in China, Japan, Kazakhstan, Korea, Mongolia, Russia. Eight species occur in China.
Sempervivoideae is the largest of three subfamilies in the Saxifragales family Crassulaceae, with about 20–30 genera with succulent leaves. Unlike the two smaller subfamilies, it is distributed in temperate climates. The largest genus in this subfamily is Sedum, with about 470 species.
Reidmorania occidentalis is a succulent plant in the stonecrop family (Crassulaceae) native to the state of Sinaloa in Mexico. It is within the monotypic genus Reidmorania, which is named after botanist Reid Moran, who was notable for his research in the Crassulaceae family.
Kalanchoideae is one of three subfamilies in the Saxifragales family Crassulaceae, with four succulent genera.
