Taxonomic evaluation of Polygonum multiflorum Thunb. var. angulatum S. Y. Liu (Polygonaceae) reveals that a new combination in Fallopia Adans. is necessary, and the name F. multiflora (Thunb.) Haraldson var. angulata (S. Y. Liu) H. J. Yan, Z. J. Fang & Shi Xiao Yu is proposed. The new variety differs from the typical one by its square branchlets with longitudinal ridges that are densely papillate and by its root tubers with a greater abundance of fibers and abnormal vascular strands evident in anatomical cross section.