The genus
Rapicactus was proposed in 1942 by Buxbaum and Oehme. It was characterized by having thick roots with a constriction above forming a neck. However, most subsequent treatments sank the genus into a broadly
circumscribed genus
Turbinicarpus. The circumscription of
Turbinicarpus has been described as "remarkably unstable", with species regularly transferred to other genera. The broad circumscription of
Turbinicarpus was recognized as
polyphyletic by Hunt in 2016. A
phylogenetic study published in 2019 showed that a
monophyletic Rapicactus was sister to
Acharagma, separated from a monophyletic
Turbinicarpus: }}
Species ,
Plants of the World Online accepted four species: ==References==