Around 125, see text.
Kalanchoe //, or kal-un-KOH-ee, or kal-un-kee, also written Kalanchöe or Kalanchoë, is a genus of about 125 species of tropical, succulent flowering plants in the family Crassulaceae, mainly native to Madagascar and tropical Africa.
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.
Kalanchoes 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. Kalanchoe flowers are divided into 4 sections with 8 stamens. The petals are fused into a tube, in a similar way to some related genera such as Cotyledon.
Name and taxonomy
Kamel's species was most likely Kalanchoe ceratophylla as he describes the plant as having deeply divided leaves. Kalanchoe ceratophylla is called 伽蓝菜 (apparently 'Buddhist temple herb') in China, not very close in pronunciation: qiélán cài or jia lan cai depending on the romanisation (but the Cantonese 'gaa laam choi' may be closer). 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.
The genus is predomiantly native to the Old World. Only one species of this genus originates from the Americas, 56 from southern & eastern Africa and 60 species in Madagascar. It is also found in south-eastern Asia and China.
Cultivation and uses
These plants are cultivated as ornamental houseplants and rock or succulent garden plants. This plant is known to the Chinese as "10,000 purple 1,000 red" (萬紫千紅, wànzǐqiānhóng), and is commonly purchased during the Chinese New Year for decorative purposes. 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 phylloclades. 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 indentations in phylloclade margins. 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. These plants are the food plant of the caterpillars of Red Pierrot butterfly. The butterfly lays its eggs on phylloclades, and after hatching, caterpillars burrow into phylloclades and eat their inside cells.
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.
- Sunset Western Garden Book, 1995:606–607; "Kalanchoe". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
- Crassulaceae Network
- 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.
- Adanson, M. Familles des Plantes
- Camel, J.G. Herbarium aliarumque stirpium in Insulâ Luzone Philippinarum Primariâ nascentium. In: John Ray: Historia plantarum. Band 3, London 1704, Anhang, S. 1–42 p. 6. item 18. 
- Chernetskyy, M.A. (2011). "Problems in nomenclature and systematics in the subfamily Kalanchoideae (Crassulaceae) over the years". Acta Agrobotanica. 6 (4): 67–74.
- eFloras Index, Flora of China.
- ird.fr: Allorge-Boiteau, L., 1996. Madagascar Centre de Spéciation et d'Origine du Genre Kalanchoe (Crassulaceae). Biogéographie de Madagascar, 1996 : 137-145
- 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 . 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.