Discocactus zehntneri var. horstiorum P.J.Braun in Succulenta (Netherlands) 69: 218. 1990
Discocactus zehntneri var. horstiorum in Succulenta (Netherlands) 69: 218. 1990
is basionym for Discocactus zehntneri subsp. horstiorum in Kakteen And. Sukk. 46: 64. 1995