Crassulaceae

Adromischus cooperii. Adromischus flower Aeonium cv.'Sunburst' Cotyledon orbiculata. Crassula ovata. Dudleya brittonii Echeveria 'Dondo'. Echeveria gibbiflora crenulata. Kalanchoe fedtschenkoi. Kalanchoe eriophylla. Monanthes. Sedum praealtum. Sempervivum arachnoidium. All photos by Laurel Woodley The family Crassulaceae has a worldwide distribution but is best represented in the Northern Hemisphere and South Africa. Members of this family occur from sea level to Montane plant communities and are generally perennials with herbaceous to shrub-like structure. Succulence is found most frequently in the leaf structure but also occurs in stems or underground caudices. Crassulaceae is subdivided into 33 genera with approximately 1,400 species, making it one of the larger succulent plant families, along with Aizoaceae and Cactaceae. Succulent leaves frequently aggregate into rosettes. Flowers are regular, five parted in general with stamens equal to or twice the number of the petals. Most distinctive are the superior ovaries which are all separate from one another and bear a nectar scale at the base. Seeds are small (1.5-3.0 mm) and released from dry follicles. This is one of the more popular succulent families due to the diverse growth forms and ease of culture. For years they have been used as hardy perennials in rock gardens and have even been used for green “living” roofs. There are no important crop plants associated with this family but some have been used in local herbal medicines. The following thirteen genera are most frequently encountered by the succulent collector: Adromischus is endemic to Namibia and South Africa with the greatest concentration of species in the succulent Karoo (W. Cape) and the Little Karoo. The 28 species can be described as small, evergreen succulent perennial herbs. They are good plants for small container culture as they normally grow among rocky outcrops. Aeonium is a genus with about 36 species and a distribution ranging from the Canary, Cape Verde and Madeira Islands to Morocco, East Africa and Southern Arabia. These biennial or mostly perennial subshrubs can be recognized by the flattish rosette of succulent leaves found at the end of the stem. Hybridization is common in this group. Cotyledon is a genus of about 10 species restricted to the Cape Province of South Africa. These perennial shrubs have succulence in both the leaves and stems. The flowers form tubular cups with spreading free lobes and are pollinated by sunbirds. Cotyledon orbiculata is locally used for medicinal purposes in the treatment of warts and abscesses. Crassula is primarily a Southern Hemisphere genus of 200 species with approximately 150 species occurring in South Africa alone, its center of diversity. Representatives of this genus occur throughout the rest of the world, as well. Plant growth ranges from small, compact herbs to arborescent shrubs up to 3.0 Meters tall ( Crassula arborescens and C. ovata ). A few are geophytes, regularly disappearing below ground during periods of drought. Leaves of many Crassula have modified stomata called hydathodes that can secrete liquid and dissolved salts from within the plant. The flowers are structurally simple with the same number (generally 5) of sepals, petals, stamens and carpels alternating with each other in whorls from the outside in. Stamens are basally attached to the petal and alternate with them. The tips of the petals often have short subterminal appendages on the outside. Dudleya includes 44 species with the greatest concentration in California’s winter rainfall regions along the coast and extending to neighboring continental islands. Species do range as far north as southwest Oregon, as far east as southern Nevada and central & western Arizona and south into Sonora and Baja, Mexico. Members of this genus are perennial leaf and stem succulents with a rosette of generally glaucous leaves at the end of the stem. Dry leaves remain attached to the stem and cover the stems. Many species produce tubular red to yellow flowers that attract Hummingbirds. Echeveria is a New World genus distributed from the southern U.S.A. to Mexico and on through Central and South America. The majority of the 135 species occur in Mexico. Members of this genus grow in light shade on rocks or on sides of cliffs and produce leaves along the stem ultimately forming a rosette at the stem end. The flowering stem has numerous bracts similar in shape to the normal leaves but smaller in size. Petals are five, imbricate and expanding slightly only near the tip. There is generally a nectar cavity at the base of the flower which attracts Hummingbirds. Echeveria is a popular subject for succulent growers along coastal areas where some cultivars produce giant rosettes of many colors and forms. Graptopetalum consists of 16 species distributed from central and southern Arizona into Mexico. These rosette plants occur on rocky sites up to 2,400 meters in elevation. The flowers are erect, stellate and usually 5-merous, remaining open from four to fourteen days. Petals are generally whitish to yellow with reddish to brown cross band markings or blotches. Stamens are recurved on maturity. This genus is closest to the genus Sedum . Kalanchoe includes 139 species occurring mainly in Madagascar and eastern and southern Africa, extending northward into tropical Africa, Arabia and tropical southeast Asia. Plants of this genus are perennial shrublets with succulent leaves and stems. Flowers are 4-merous with petals united to form a tube with erect, spreading or reflexed shorter lobes. Stamens are 8 in number, occurring in two whorls. This group is generally easy to cultivate and propagation is by stem cuttings, rooted leaves or bulbils. Monanthes occurs on the Canary and Selvagens Islands and contains 9 species. Most are small annual or perennial herbs or shrublets. Flowers are small with stamens twice the number of petals. The stamen filament is depressed by the nectary where the nectar sac is conspicuously enlarged as a bilobed structure. Pachyphytum includes 15 species all of which occur on rocky sites in eastern and central Mexico. This group is perennial with glabrous succulent leaved rosettes that have erect stems at first while later becoming decumbent. The inflorescence has bract leaves at the base of a strongly arching stem that later becomes more erect. The flowers are tubular, barrel-shaped or campanulate, often with a red spot at the base of the petal. A scale-like appendage of the corolla lobe is an outgrowth of the petal margin. This genus appears closest to the genus Echeveria . Sedum , generally known as Stonecrops, is the largest genus of the family with 420 species. Its distribution is subtropical and temperate zones of the Northern Hemisphere with the greatest species richness in the New World with 170 species. Asia is second in richness with 130-140 species and Eurasia last with 100 species. This genus is made up of perennial herbaceous succulent leaved plants that have long been popular with gardeners for there ease of cultivation. Flowers are 5-merous with the stamen number being twice the number of the petals, occurring in two whorls. The inner whorl is fixed to the petals while the outer whorl is fixed between the petals. In Sedum the carpels are beaked (style) and seeds are released when the follicle splits vertically. Sempervivum is an Old World genus of 46 species found in Europe, northwest and central Russia, the Balkan Peninsula, Carpathians, Turkey, Iran, Caucasus to Morocco. These low growing rosette forming plants are a conspicuous element of alpine and mountainous floras of central and southern Europe and Anatolia. They probably evolved from an old polyploidy Sedum lineage. Tylecodon is restricted to Namibia and South Africa with the concentration of species in the Richtersveld and Knersvlakte. There are 44 species of these perennial deciduous herbs and shrublets which frequently present a caudiciform base and sometimes grow 2.5 Meters in height. Active growth is during autumn to early summer during the rainy season and flowering follows in the summer when the leaves have fallen. The 5-merous flowers are tubular to funnel shaped with fruit of erect follicles, only dehiscent apically. This genus is closely related to Cotyledon and Adromischus . Tylecodon is an anagram of Cotyledon . Family: Crassulaceae Higher Classification: Angiospermae: Dicotyledonae Genera of succulent species: Adromischus, Aeonium, Aichryson, Cotyledon, Crassula, Dudleya, Echeveria, Graptopetalum, Hylotelephium, Kalanchoe, Lenophyllum, Monanthes, Orostachys, Pachyphytum, Phedimus, Pistorinia, Prometheum, Pseudosedum, Rhodiola, Rosularia, Sedella, Sedum, Sempervivum, Sinocrassula, Thompsonella, Tylecodon, Umbilicus, Villadia Distribution of succulent species: Worldwide but especially Northern Hemisphere and South Africa Growth form of succulent species: Perennial (rarely annual) herbs, subshrubs to shrubs, usually with succulent leaves or sometimes succulent stems or underground caudices