Comparative leaf anatomy, FTIR discrimination and biogeographical analysis of Camellia section Tuberculata (Theaceae) with a discussion of its taxonomic treatments

Abstract

A comparative anatomical and FTIR study on the leaves of 18 disputed species of section Tuberculata (Camellia, Theaceae) combined with their biogeographical distribution have been conducted in order to investigate interspecific variations which are useful in species taxonomic treatment and systematic evolution. All Tuberculata species have bifacial and hypostomatic leaves, contain sclereids and crystals. Multivariate analysis of leaf FTIR data shows a visualization of the degree of affinity among the species in this section, which is consistent with the distribution of synonymous Tuberculata species indicated in the biogeographical maps. Our study indicates that the combination of characters based on leaf comparative anatomy, FTIR analysis and biogeographical distribution are useful in species revision. The results determine 11 species in section Tuberculata and provide the evolutionary trends in Tuberculata, which originated in three-river region of Guizhou province and spread to Guizhou, Guangxi, Yunnan, Sichuan, Chongqing, Hunan and probably Hubei provinces of China.