Study of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA, combined with morphological data, have yielded a better-resolved phylogenetic hypothesis, confirming the distinctiveness of the above-named genera.
The Tokugawa's clan crest, known in Japanese as a "mon", the "triple hollyhock" (although commonly, but mistakenly identified as "hollyhock", the "aoi" actually belongs to the birthwort family and translates as "wild ginger"—Asarum), has been a readily recognized icon in Japan, symbolizing in equal parts the Tokugawa clan and the last shogunate.