Rapicactus

Phylogenetics: Traditionally included in Turbinicarpus, separated from it by Vázquez-Sánchez & al. (2013) after Turbinicarpus was found to be polyphyletic by them and previously also by Bárcenas & al. (2011). Subsequent evidence indicated that Rapicactus was an independent lineage of Turbinicarpus s.s. The presence of concentric druses in the hypodermis is a feature present in the members of Rapicactus (De la Rosa-Tilapa et al. 2018). Vázquez-Sánchez et al. (2019) performed a phylogenetic study that included five molecular markers (matK, rbcL, psbA-trnH, rpl16 and trnL-F) and anatomical characters. Rapicactus was recovered as monophyletic with maximal support as sister to Acharagma, Lophophora and Obregonia. In conclusion, Rapicactus is a lineage independent from Turbinicarpus s.s. Five species and four subspecies are recognized, of which Rapicactus beguini is the species with the greatest morphological variation (See treatment).A