Kalanchoe

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 open 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.[5]

• 
  Kalanchoe luciae
• 
  Kalanchoe delagoensis
• 
  Kalanchoe thyrsiflora
• 
  Kalanchoe marmorata
• 
  Kalanchoe tomentosa
• 
  Kalanchoe beharensis
• 
  Kalanchoe 'Tarantula'
• 
  K. delagoensis × K. daigremontiana
• 
  Flaming katy - Kalanchoe blossfeldiana

The genus Kalanchoe was first described by the French botanist Michel Adanson in 1763.[6]

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, while Bryophyllum has also been treated as a separate genus,[6] since species of Bryophyllum appear to be nested within Kalanchoe on molecular phylogenetic analysis, Bryophyllum is considered as a section of the former, dividing the genus into three sections, Kitchingia, Bryophyllum, and Eukalanchoe.[7][8][9] these were formalised as subgenera by Smith and Figueiredo (2018).[1]

The genus is predominantly native to the Old World. Only one species originates from the Americas. 56 are from southern and eastern Africa and 60 species on the island of Madagascar. It is also found in south-eastern Asia and China.[15]

These plants are food plants for caterpillars of the Red Pierrot butterfly. The butterfly lays its eggs on leaves, and after hatching, caterpillars burrow into the leaves and eat their inside cells.

Production of new individuals along a leaf margin of the air plant, Kalanchoe pinnata. The small plant in front is about 1 cm tall

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 leaves. 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 leaf 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: Kalanchoe daigremontiana is thus an example of asexual reproduction.[16]

The cultivars ‘Tessa’[17] and ‘Wendy’ have gained the Royal Horticultural Society’s Award of Garden Merit.[18][19]

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.[20]

A variety of bufadienolide compounds have been isolated from various Kalanchoe species. Five different bufadienolides have been isolated from Kalanchoe daigremontiana.[21][22] 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.[23] Bryophillin C also showed insecticidal properties.[24]

• Media related to Kalanchoe at Wikimedia Commons
• Data related to Kalanchoe at Wikispecies