The composition of root chemicals was studied for 7 samples of Ligularia tongolensis collected in Yunnan and Sichuan Provinces of China. The structures of 2 new 3β-angeloyloxy-6β-acyloxyfuranoeremophilan-15-oic acids were determined. It was found that the plant harbors chemical diversity in the acyloxy groups in 3,6-bis(acyloxy)eremophilan-15-oic acids. The presence of a 3-methylpentanoate moiety at C-3 appears geographically differentiated to a degree. Consistent with this low diversity, results of DNA analysis indicated little genetic differentiation, although introgression was inferred for one of the samples.

Two intergeneric hybrids between Ligularia nelumbifolia and Cremanthodium stenoglossum were examined with respect to the chemical composition of root extracts and the sequences of neutral DNA regions. The DNA data showed that the direction of hybridization was different between the individuals. Eremophilane sesquiterpenes were found in both hybrids and deduced to have come from their Cremanthodium parents, because sesquiterpenes were detected in C. stenoglossum but not in L. nelumbifolia.

Root chemicals and the sequences of the internal transcribed spacers (ITSs) were analyzed for 9 Ligularia kanaitzensis and 3 L. subspicata samples collected in northwestern Yunnan and southwestern Sichuan, China. Subspicatins A and C were isolated from two L. kanaitzensis samples. Introgression of genes responsible for these compounds from L. subspicata was suggested by their strong connection with L. subspicata/L. lamarum and the geographical proximity of the samples to L. subspicata. DNA analysis of a set of 27 L. kanaitzensis samples including those analyzed previously showed that they belong to two clades, designated A and B. Together with the presence/absence of furanoeremophilane, the 27 samples were sorted into three groups: clade A/furan, clade B/furan, and clade B/non‐furan. The ancestral plant presumably belonged to clade B/non‐furan, because furanoeremophilanes are biosynthesized from eremophilan‐8‐ones. 1β‐Angeloyloxyfukinone, a likely intermediate between fukinone and subspicatin C, was isolated for the first time. This finding allowed us to propose plausible biosynthetic pathways of subspicatins A and C.