Escobaria zilziana subsp. fricii Halda & Sladk. in Acta Mus. Richnov., Sect. Nat., 7: 35. 2000
Escobaria zilziana subsp. fricii in Acta Mus. Richnov., Sect. Nat., 7: 35. 2000
Holotype: Mexico, Coahuila, Sierra de la Paila, in the vicinity of Castanos [Castaños], alt. 2000 m, 13 Apr 1985, J. J. Halda & J. Sladkovský (PR: JJH&JS8504013520)