Ritz, C.M., Fickenscher, K., Föller, J., Herrmann, K., Mecklenburg, R. & Wahl, R. 2016: Molecular phylogenetic relationships of the Andean genus Aylostera Speg. (Cactaceae, Trichocereeae), a new classification and a morphological identification key. – Plant Systematics and Evolution 302(7): 763-780

The Andes represent a hotspot of diversity within Cactaceae. Owing to its small globular growth and its diverse flower colours the Andean genus Aylostera Speg. has drawn the attention of many cactus enthusiasts. Based on molecular data, the genus was recently split from Rebutia s.l. In contrast to the large number of taxa described within Aylostera, a comprehensive phylogenetic reconstruction is still warranted. The aim of our study was to reconstruct a phylogeny of Aylostera and to review its taxonomy based on morphological characters. We sequenced the chloroplast DNA markers atpB-rbcL and trnS-trnG intergenic spacers and scored amplified fragment lengths polymorphisms (AFLPs). We reconstructed phylogenetic trees and analysed results of AFLP neighbour-nets, Bayesian clustering and Principal Coordinate Analysis based on this genetic data. Our data demonstrated that Aylostera is monophyletic and is best recognized as a separate genus because it is only distantly related to the clade containing the type species of Rebutia. Within Aylostera we detected three clades—the Digitorebutia clade, the Aylostera sensu stricto clade and the A. einsteinii clade—which are characterized by unique combinations of morphological character states. The species composition of these clades was largely congruent between the molecular markers but AFLP data indicated some admixture. Based on genetic and morphological characters, we propose a new classification of Aylostera and present a key to species recognizing nine species.