Problems in nomenclature and systematics in the subfamily kalanchoideae (Crassulaceae) over the years

Ambiguity concerning the systematics and nomenclature of the subfamily Kalanchoideae has been observed in the family Crassulaceae. In the history of research on representatives of the above-mentioned systematic group, there have been two opposing viewpoints aiming at either the establishment of separate genera Bryophyllum, Kalanchoë and Kitchingia or combining all the species into one genus Kalanchoë divided into subgenera (Bryophyllum, Calophygia, Kalanchoë) or sections (Bryophyllum, Kalanchoë (Eukalanchoë) and Kitchingia or Bryophyllum, and Kalanchoë. According to the analysis of various morphological, anatomical, embryological, karyological, phytogeographical, molecular genetics researches, it is challenging to establish the three genera in the subfamily Kalanchoideae due to the existence of intermediate species. Taking also into account the results of his own research, the author of the present work postulates that the most appropriate taxonomic approach is to recognize one genus Kalanchoë with the division into three sections: Bryophyllum, Kalanchoë and Kitchingia. The names of two of these sections correspond with the previously adopted names of the genera, thus referring to the initial stages of research concerning this subfamily