Bryophyllum (from the Greek bryon/bryein = sprout, phyllon = leaf) is a group of plant species of the family Crassulaceae native to Madagascar. It is a section or subgenus within the genus Kalanchoe, and was formerly placed at the level of genus. This section is notable for vegetatively growing small plantlets on the fringes of the leaves; these eventually drop off and root. These plantlets arise from mitosis of meristematic-type tissue in notches in the leaves.
Nowadays, bryophyllums are naturalized in many parts of the tropics and subtropics, and deliberately cultivated for their attractiveness or for their interesting reproduction as a vegetative reproductive plant.
Taxonomy
Species of Bryophyllum are nested within Kalanchoe on molecular phylogenetic analysis. Therefore, Bryophyllum should be a section of Kalanchoe rather than a separate genus.
The number of species within Bryophyllum varies with definitions of this section. Bryophyllum used to include not only species that produce plantlets on the leaf margin, but also many species that lack this character such as K. manginii and K. porphyrocalyx. However, the broadly defined Bryophyllum is polyphyletic. Bernard Descoings redefined Bryophyllum as 26 species, and molecular phylogenetic analysis shows that his definition is almost monophyletic, except that K. beauverdii (hence as well as its hybrid K. × poincarei) and K. delagoensis (hence as well as its hybrids K. × houghtonii and K. × richaudii) should be included and K. pubescens excluded. Therefore, Bryophyllum comprises about 30 species: Kalanchoe beauverdii Kalanchoe bogneri Kalanchoe cymbifolia Kalanchoe daigremontiana Kalanchoe delagoensis Kalanchoe fedtschenkoi Kalanchoe gastonis-bonnieri Kalanchoe × houghtonii: K. daigremontiana × K. delagoensis Kalanchoe humifica Kalanchoe × laetivirens: K. daigremontiana × K. sp. (probably K. laxiflora) Kalanchoe laxiflora Kalanchoe × lokarana: K. laxiflora × K. sp. Kalanchoe macrochlamys Kalanchoe marnieriana Kalanchoe maromokotrensis Kalanchoe mortagei Kalanchoe peltigera Kalanchoe pinnata Kalanchoe × poincarei: K. beauverdii × K. sp. Kalanchoe prolifera Kalanchoe × rechingeri: K. beauverdii × K. sp. (K. delagoensis or K. rosei) Kalanchoe × richaudii: K. delagoensis × K. rosei Kalanchoe rosei Kalanchoe rubella Kalanchoe sanctula Kalanchoe serrata Kalanchoe streptantha Kalanchoe suarezensis Kalanchoe tenuiflora Kalanchoe waldheimii
Toxicity
Several species of Kalanchoe are economically important for causing cardiotoxic effects in sheep and cattle, and diseases affecting the nervous system and muscles known as krimpsiekte ("shrinking disease") or as cotyledonosis. Kalanchoe pinnata may have similar chemical components, bufadienolide alkaloids.