Recircumscription of Begonia sect. Baryandra (Begoniaceae): evidence from molecular data

Rosario Rivera Rubite,Grecebio Jd Alejandro,Ching-I Peng,Mark Hughes

doi:10.1186/1999-3110-54-38

Abstract

BackgroundBegonia sect. Diploclinium is a ‘dust-bin’ section for species retaining pleisiomorphic characters and lacking novel synapomorphic characters used to delimit other Asian sections in Begonia. Part of this large and polymorphous section is transferred to Begonia sect. Baryandra in a move towards a more natural classification for the genus.ResultsPhylogenetic analysis of nuclear ribosomal ITS DNA sequences show a strongly supported monophyletic group containing Philippine and Bornean species previously in Begonia sect. Diploclinium, and the type of Begonia sect. Baryandra, B. oxysperma. This clade forms the basis for the now much-expanded Begonia sect. Baryandra, which as defined here contains 49 species and has its centre of diversity in the Philippines.ConclusionsA natural classification for a much expanded Begonia sect. Baryandra has been provided. This paper highlights the feasibility of moving towards a natural classification of Asian Begonia step by step as information comes to light through building upon previous framework phylogenies with denser sampling.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-38) contains supplementary material, which is available to authorized users.

Highlights

This paper highlights the feasibility of moving towards a natural classification of Asian Begonia step by step as information comes to light through building upon previous framework phylogenies with denser sampling
Infrageneric ranks take over the function of the genus as it is used for less species-rich groups; subgenera or sections are able to divide large genera into more manageable units for discussing and communicating biological information
The lack of distinguishing characters for the section has been highlighted by Shui et al, (2002) who note its similarity to other Asian sections and the New World Begonia sect

Summary

Introduction

Diploclinium is a ‘dust-bin’ section for species retaining pleisiomorphic characters and lacking novel synapomorphic characters used to delimit other Asian sections in Begonia. Part of this large and polymorphous section is transferred to Begonia sect. Sub-generic taxa have another use in that they allow one to freely move species from one higher taxon to another without having to formally publish new combinations and leaving an untidy nomenclatural trail. This is relevant for using the rank of section in Begonia.

Methods

Results

Conclusion