A Phylogenetic Study On The Genus Neolitsea Merr. (Lauraceae)

The genus Neolitsea Merr. (Lauraceae), with about 100 species, occurs mainly in tropical-subtropical Asia. China is a centre of diversity for the genus, with 45 species distributed from southwest, south to east in the country. Neolitsea is often characterised by its dimerous flowers, six anthers, clustered, triplinerved leaves and sessile sub-umbels. Our research based on the former systematic studies of Lauraceae, using molecular phylogenetic and morphological analysis to solve the systematic problems of the genus Neolitsea and draw some preliminary conclusions.In molecular phylogenetic analysis, we used nrDNA ITS (Internal Transcribed Spacer) and ETS (External Transcribed Spacer) sequences as the molecular evidence. Then, MP (Maximum Parsimony) and BI (Bayesian Inference) were used to analyze the obtained data sets (ITS, ETS and ETS & ITS). Finally, the ETS & ITS Bayesian consensus tree was considered as the most accurate result to reflect the phylogeny of Neolitsea. In morphological analysis, 30 morphological characters were chosen for coding. We used MP method to analyze the obtained morphological data matrix, and finally chose 8 morphological characters to map on the ETS & ITS Bayesian consensus tree.Based on the results of molecular phylogenetic and morphological analysis, we indicated that Neolitsea was monophyletic and had very close relationships with most sampled Actinodaphne taxa. We also indicated that the inflorescence features might be a most important character for explaining relationships between Neolitsea and other genera within the'core'Laureae. Although the relationships within Neolitsea are poorly resolved, there was enough evidence to suggest that the genus could be divided into two groups based on fruit shape: globose, versus elliptic or ovoid.