Around 125, see text.
Kalanchoe (pron.: //), also written Kalanchöe or Kalanchoë, is a genus of about 125 species of tropical, succulent flowering plants in the family Crassulaceae, mainly native to the Old World but with a few species now growing wild in the New World following introduction of the species.
Most are shrubs or perennial herbaceous plants, but a few are annual or biennial. The largest, Kalanchoe beharensis from Madagascar, can reach 6 m (20 ft) tall, but most species are less than 1 m (3 ft) tall.
The genus was first described by the botanist Michel Adanson in 1763. Reportedly, the name came "from the Chinese name for one of the species."  This Chinese species is thought to have been either Kalanchoe ceratophylla or Kalanchoe spathulata. Kalanchoe ceratophylla is called 伽蓝菜 in China, not very close in pronunciation: qiélán cài or jia lan cai depending on the romanisation. The genus Bryophyllum was described by Salisbury in 1806 and the genus Kitchingia was created by Baker in 1881. Kitchingia is now regarded as a synonym for Kalanchoe, whereas some botanists treat Bryophyllum as a separate genus.
Cultivation and uses 
These plants are cultivated as ornamental houseplants and rock or succulent garden plants. This plant is known to the Chinese as "thousands and millions of red and purple" (萬紫千紅), and is commonly purchased during the Chinese New Year for decorative purposes.Empty citation (help) They are popular because of their ease of propagation, low water requirements, and wide variety of flower colors typically borne in clusters well above the vegetative growth. The section Bryophyllum - formerly an independent genus - contains species such as the "Air plant" Kalanchoe pinnata. In these plants, new individuals develop vegetatively as plantlets, also known as bulbils or gemmae, at indents along the leaves. These young plants eventually drop off and take root. No males have been found of one species of this genus which does flower and produce seeds, and it is commonly called, the Mother of Thousands; the Kalanchoe daigremontiana is thus an example of asexual reproduction (not so common for leaves). These plants are the food plant of the caterpillars of Red Pierrot butterfly. The butterfly lays its eggs on the leaf and after hatching the caterpillar goes inside the leaf and eats the leaf from inside.
Toxicity and traditional medicine 
In common with other Crassulaceae (such as the genera Tylecodon, Cotyledon and Adromischus), some Kalanchoe species contain bufadienolide cardiac glycosides which can cause cardiac poisoning, particularly in grazing animals. This is a particular problem in the native range of many Kalanchoe species in the Karoo region of South Africa, where the resulting animal disease is known as krimpsiekte (shrinking disease) or as cotyledonosis. Similar poisonings have also occurred in Australia.
In traditional medicine, Kalanchoe species have been used to treat ailments such as infections, rheumatism and inflammation. Kalanchoe extracts also have immunosuppressive effects. Kalanchoe pinnata has been recorded in Trinidad and Tobago as being used as a traditional treatment for hypertension.
A variety of bufadienolide compounds have been isolated from various Kalanchoe species. Five different bufadienolides have been isolated from Kalanchoe daigremontiana.  Two of these, daigremontianin and bersaldegenin 1,3,5-orthoacetate, have been shown to have a pronounced sedative effect. They also have the strong positive inotropic effect associated with cardiac glycosides, and with greater doses an increasing effect on the central nervous system.
Bufadienolide compounds isolated from Kalanchoe pinnata include bryophillin A which showed strong anti-tumor promoting activity, and bersaldegenin-3-acetate and bryophillin C which were less active. Bryophillin C also showed insecticidal properties.
Selected species 
- Sunset Western Garden Book, 1995:606–607; "Kalanchoe". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005.
- Baldwin Jr., J. T. (October 1938). "Kalanchoe: The Genus and its Chromosomes". American Journal of Botany 25 (8): 572–579. doi:10.2307/2436516. JSTOR 2436516
- eFloras Index, Flora of China.
- REPRODUCTIVE STRATEGIES: PLANTS. (1999). In Encyclopedia of Paleontology. Retrieved from http://www.credoreference.com/entry/routpaleont/reproductive_strategies_plants .
- Steyn, Pieter S; van Heerden, Fanie R. (1998). "Bufadienolides of plant and animal origin". Natural Product Reports. Royal Society of Chemistry. Retrieved 2007-09-19.
- McKenzie, RA; Dunster PJ. (July 1986). "Hearts and flowers: Bryophyllum poisoning of cattle". Australian veterinary journal 63 (7): 222–7. doi:10.1111/j.1751-0813.1986.tb03000.x. PMID 3778371.
- McKenzie, RA; Franke FP, Dunster PJ. (October 1987). "The toxicity to cattle and bufadienolide content of six Bryophyllum species". Australian veterinary journal 64 (10): 298–301. doi:10.1111/j.1751-0813.1987.tb07330.x. PMID 3439945.
- Hilton-Taylor, Craig. "How Dangerous are Euphorbias? (And Others in the Family Euphorbiaceae) with some comments on dangerous plants in the families Agavaceae, Aizoaceae, Apocynaceae, Compositae, Crassulaceae, Liliaceae". Retrieved 2007-09-19.
- Lans, CA (2006-10-13). "Ethnomedicines used in Trinidad and Tobago for urinary problems and diabetes mellitus". Journal of ethnobiology and ethnomedicine 2: 45. doi:10.1186/1746-4269-2-45. PMC 1624823. PMID 17040567.
- Wagner, H; Fischer M, Lotter H (April 1985). "Isolation and Structure Determination of Daigremontianin, a Novel Bufadienolide from Kalanchoe daigremontiana". Planta medica 51 (2): 169–70. doi:10.1055/s-2007-969441. PMID 3839925.
- Supratman, U; Fujita T, Akiyama K, Hayashi H (September 2001). "Insecticidal compounds from Kalanchoe daigremontiana x tubiflora". Phytochemistry 58 (2): 311–4. doi:10.1016/S0031-9422(01)00199-6. PMID 11551556.
- Supratman, U; Fujita T, Akiyama K, Hayashi H, Murakami A, Sakai H, Koshimizu K, Ohigashi H (April 2001). "Anti-tumor promoting activity of bufadienolides from Kalanchoe pinnata and K. daigremontiana x tubiflora". Bioscience, Biotechnology, and Biochemistry 65 (4): 947–9. doi:10.1271/bbb.65.947. PMID 11388478.
- Supratman, U; Fujita T, Akiyama K, Hayashi H (June 2000). "New insecticidal bufadienolide, bryophyllin C, from Kalanchoe pinnata". Bioscience, Biotechnology, and Biochemistry 64 (6): 1310–2. doi:10.1271/bbb.64.1310. PMID 10923811.
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