Frailea horstii F.Ritter, Kakteen Südamerika 1: 202. 1979
Frailea horstii, Kakteen Südamerika 1: 202. 1979
is basionym for Frailea gracillima subsp. horstii in Succulenta (Netherlands) 74(3): 130. 1995
is basionym for Astrophytum horstii in Acta Mus. Richnov., Sect. Nat., 12(1): 13. 2005