A new status for two varieties previously included in the southern Malagasy Kalanchoe rosei, now included in K. variifolia (Crassulaceae subfam. Kalanchooideae)

Kalanchoe rosei (Crassulaceae subfam. Kalanchooideae) is a phyllo-bulbiliferous species endemic to southern Madagascar. Historically, two varieties, K. rosei var. seyrigii and K. rosei var. variifolia, have been recognised in K. rosei. One of the two specimens cited when K. rosei var. seyrigii was described bears much resemblance to K. peltigera. However, regardless of how K. rosei var. seyrigii was originally described, the type of the name K. rosei var. seyrigii, which determines its application, is that of the synonym it replaced, i.e., K. rosei subsp. serratifolia. The two varieties, K. rosei var. seyrigii and K. rosei var. variifolia, were originally described as subspecies and are sometimes treated at that rank, as K. rosei subsp. serratifolia and K. rosei subsp. variifolia. Kalanchoe rosei var. seyrigii and K. rosei var. variifolia are morphologically very similar and, based on reproductive morphology alone, can hardly be distinguished, which reaffirms the close relationship between them. Kalanchoe rosei is most closely related to K. peltigera, as well as to K. daigremontiana, K. laetivirens, and K. sanctula, a group of pink-flowered constitutively phyllo-bulbiliferous species from Madagascar. In contrast, K. rosei var. seyrigii and K. rosei var. variifolia rather share several morphological similarities with orange-flowered representatives included in the informal group “Suffrutescentes”, and frequently hybridise with them. Kalanchoe rosei var. variifolia is here elevated to species rank, as K. variifolia, for material hitherto treated as belonging to K. rosei var. seyrigii and K. rosei var. variifolia. Two varieties, the autonymic one and K. variifolia var. seyrigii, are recognised in K. variifolia. The typification of K. rosei subsp. variifolia and K. rosei var. seyrigii, the basionyms of K. variifolia var. variifolia and K. variifolia var. seyrigii, respectively, is clarified.