Discocactus zehntneri subsp. boomianus (Buining & Brederoo) N.P.Taylor & Zappi in Bradleya 9: 86. 1991 sec. Zappi & Taylor 2020
- ≡Discocactus boomianus Buining & Brederoo in Succulenta (Netherlands) 50: 26. 1971 syn. sec. ???
- ≡Discocactus zehntneri var. boomianus (Buining & Brederoo) P.J.Braun in Succulenta (Netherlands) 69: 218. 1990 syn. sec. ???
- =Discocactus araneispinus Buining & Brederoo, Discocactus: 39. 1976 syn. sec. Taylor & Zappi 2004
- ≡Discocactus zehntneri var. araneispinus (Buining & Brederoo ex J.Theun.) P.J.Braun in Succulenta (Netherlands) 69: 215. 1990 syn. sec. Taylor & Zappi 2004
- ≡Discocactus zehntneri subsp. araneispinus (Buining & Brederoo) P.J.Braun & Esteves in Kakteen And. Sukk. 46: 64. 1995 syn. sec. Taylor & Zappi 2004
- =Discocactus zehntneri var. horstiorum P.J.Braun in Succulenta (Netherlands) 69: 218. 1990 syn. sec. Taylor & Zappi 2004
- ≡Discocactus zehntneri subsp. horstiorum (P.J.Braun) P.J.Braun & Esteves in Kakteen And. Sukk. 46: 64. 1995 syn. sec. Taylor & Zappi 2004