Further insights and new combinations in Aylostera (Cactaceae) based on molecular and morphological data.

The Genus Rebutia K. Schum. is a taxonomically complex genus of Cactaceae subfamily Cactoideae. This genus was subjected to splitting and lumpering treatments through the years. Molecular data revealed that Rebutia sensu lato must be divided in a clade corresponding to former Rebutia section Rebutia (Rebutia sensu stricto), related to the clade formed by Weingartia/Cintia/Sulcorebutia. Only this clade corresponds to genus Rebutia in our results. The other sections of Rebutia s. l. (Aylostera, Digitorebutia, Cylindrorebutia) cluster together to form another clade not directly related to Rebutia s. str. For priority reason this clade is recombined as genus Aylostera Speg. An analytical key is provided, to identify genera Rebutia K. Schum., Aylostera Speg., and Weingartia Werderm. (including Sulcorebutia Backeb. and Cintia Knize & Riha) and in Aylostera, at infrageneric level, the subgenera Aylostera and Mediolobivia. Further investigations are needed to assume taxonomic decisions about the clade Weingartia/Sulcorebutia/Cintia that, as a whole, should be assigned to genus Weingartia Werderm. A list of taxa belonging to genera Rebutia K. Schum. and Aylostera Speg., is provided. In this treatment the necessary combinations following the separation of Aylostera as a genus autonomous from Rebutia are proposed. The ATPB-rbcL IGS fragment revealed to be enough variable to be used for Barcoding of species among Cactaceae. All species here considered are in CITES appendix II, with frequent determination difficulties.