From Folk Taxonomy to Species Confirmation of Acorus (Acoraceae): Evidences Based on Phylogenetic and Metabolomic Analyses

Abstract

Plants in <i>Acorus</i> have been used as herbal medicine by various linguistic groups for thousands of years. Arguments of taxonomy of <i>Acorus</i> among scientists resulted in confusions and misuses of <i>Acorus</i> plants. The present study used different methods to investigate the classification of the genus, based on folk taxonomy. The relationships among <i>Acorus</i> species were revealed through phylogenetic analyses by constructing the Maximum Likelihood and Bayesian phylogenetic analyses based on sequences of two chloroplast regions (<i>trnL-trnF</i> and <i>rbcL</i>). All samples named with two so-called synonyms, <i>Acorus macrospadiceus</i> (Yamam.) F. N. Wei and Y. K. Li and <i>Acorus tatarinowii</i> Schott collected from different habitats, were clustered into separate groups, which revealed that they represented two independent species. Multivariate statistical analysis of metabolites from different <i>Acorus</i> populations were carried out based on UPLC-QTOF-MS data. Three independent analysis, principal component analysis, heat-map analysis, and hierarchical cluster analysis, showed that <i>A. macrospadiceus</i> and <i>A. tatarinowii</i> are different from two recognized species in the genus, <i>A. calamus</i> L. and <i>A. gramineus</i> Aiton. The results of phylogenetics and chemotaxonomy, together with morphological and ecological evidences, were consistent with traditional knowledge of local people related to <i>Acorus</i> taxa, which proved the significance of parataxonomy. Multiple evidences including morphological, ecological, folk taxonomic, phylogenetic, and chemical taxonomic results suggested that there are four species in the genus <i>Acorus</i>.