Patterns of genetic variation and morphology support the recognition of five species in the Gaultheria leucocarpa Blume (Ericaceae) group from mainland China.

Abstract

Gaultheria leucocarpa and its varieties form a clade of aromatic shrubs that is widely distributed in subtropical and East Asian tropical regions. The group is taxonomically difficult and in need of thorough taxonomic investigation. This study focused on taxonomic delimitation within the G. leucocarpa group from mainland China. Field surveys covering the distributional range of G. leucocarpa in mainland China were conducted, wherein four populations from Yunnan and one from Hunan were found bearing morphological and habitat differences. A 63-species phylogenetic tree of Gaultheria based on one nuclear and three chloroplast markers that included samples from the G. leucocarpa group was reconstructed with maximum likelihood to clarify the monophyly of the G. leucocarpa group. Taxonomic relationships among populations were investigated with morphology and population genetics, the latter by using two chloroplast genes and two low-copy nuclear genes. Based on the sum of morphological and genetic analyses, we described three species of Gaultheria as new to science, clarified the taxonomic status of G. leucocarpa var. pingbienensis, elevating it to the species level, and resurrected G. crenulata and treated the varieties G. leucocarpa var. crenulata, and G. leucocarpa var. yunnanensis as synonyms of this species. We provide a key to the five species now recognized, along with descriptions and photographs.