This name is a synonym.
* Betula alnus var. rugosa Du Roi, Diss. Inaug. Obs. Bot.: 32 (1771).
Betula rugosa (Du Roi) Ehrh., Beitr. Naturk. 3: 21 (1788).
Alnus rugosa (Du Roi) Spreng., Syst. Veg. 3: 848 (1826).
Alnus serrulata var. rugosa (Du Roi) Regel, Bull. Soc. Imp. Naturalistes Moscou 38(II): 432 (1865).
Alnus incana subsp. rugosa (Du Roi) R.T.Clausen, Cornell Univ. Agric. Exp. Sta. Mem. 291: 8 (1949).
* Basionym/Replaced Synonym