Mammillaria heyderi var. macdougalii (Rose) L.D.Benson in Proc. Calif. Acad. Sci., ser. 4, 25: 265. 1944
Mammillaria heyderi var. macdougalii in Proc. Calif. Acad. Sci., ser. 4, 25: 265. 1944
is new combination for Mammillaria macdougalii, Stand. Cycl. Hort. 4: 1982. 1916