Asarum hetrotropoides Fr. Schmidt has great kinship to A. Sieboldii Miq. The latter and A. heterotropoides var. mandshuricum Kitagawa are both differentiated from this species. And A. Sieboldii var. pubinervis F. Maekawa may be an intermediate betweenA. heterotropoides and A. Sieboldii. A. Sieboldii var. cineoliferum Fujita in south-western Japan was formed by the isolation with Fossa Magna. The characteristics of this variety are the occurrence of cineole and the absence of eucarvone in essential oil. All species of the subgenus Heterotropa in Japan are differentiated somewhat later and the species which contain elemicine are considered to be derived from the one containing safrol and eugenol. A. canadense Linn. of North America which affords the essential oil containing d-linalool, geraniol and l-α-terpineol together with eugenol and methyleugenol is probably a mother species of this genus. A. caudatum Lindl. and A. europaeum Linn. are supposed to arise from this species successively. Subgenus Hexastylis in the North America, subgenera Asiasarum, Japonasarum and Heterotropa in the Eastern Asia are all considered to be radiated from the subgenus Euasarum Through A. canadense separately.