This giant rhizomatous herb from the Sachalin Islands has spread form northeastern states down the Ohio Valley into ne. Ky. within recent decades. It deserves further attention as a potentially invasive species. The hybrid with japonica ( X bohemica J. Chrtek & A. Chrtkova) has also been reported from Ky., and it is often confused with these species (FNA 5). In addition to gross morphological intermediacy, the hybrid differs from japonica in having leaf blades "obscurely puberulent along some veins abaxially, tips of hairs acute" (versus obscurely scabrous, with blunt tips).