Kalanchoe, also written Kalanchöe or Kalanchoë and pronounced /ˌkælənˈkoʊ.iː/, 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.
Most are shrubs or perennial herbaceous plants, but a few are annual or biennial. The largest, Kalanchoe beharensis from Madagascar, can reach 6 m tall, but most species are less than 1 m tall.
Members of Kalanchoe genus are characterized by opening their flowers by growing new cells on the inner surface of the petals to force them outwards, and on the outside of the petals to close them.
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. 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.
These plants are cultivated as ornamental houseplants and rock or "succulent" garden plants. 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. These plants are the food plant of the caterpillars of Red Pierrot butterfly. The butterfly lay its eggs on the leaf and after hatching the caterpillar go inside the leaf and eat the leaf from inside.
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 Karroo 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.
1. ^ Sunset Western Garden Book, 1995:606–607; "Kalanchoe". Oxford English Dictionary. Oxford University Press. 2nd ed. 1989.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License