Mammillaria sempervivi f. tetracantha (DC.) Schelle, Handb. Kakteenkult.: 269. 1907
Mammillaria sempervivi f. tetracantha, Handb. Kakteenkult.: 269. 1907
is new combination for Mammillaria sempervivi var. tetracantha, Mém. Mus. Hist. Nat. 17: 114. 1828