Molecular phylogeny of Boesenbergia (Zingiberaceae) reveals shared characters and infrageneric division

Abstract

The classification of Boesenbergia (Zingiberaceae) has long been a challenge, and recent insights from molecular phylogenetic studies have both raised and resolved a number of questions. Combined morphological and molecular revisions resulted in the description of new species as well as merging of Haplochorema and Jirawongsea into Boesenbergia. This study uses the most complete set of Boesenbergia accessions and sister genera to investigate the evolutionary relationships of the genus in a phylogenetic framework. This framework confirms the previously identified clades and the placement of the included accessions within those clades. These clades share being single-flowered and having a basipetalous flowering sequence, characters uniting all taxa in Boesenbergia, but also have unique or mostly unique characters that are clade specific. In addition, the phylogeny identifies two species, B. purpureorubra and B. siamensis, that are hard to place within these clades based on both molecular and morphological data, while the morphological data points to a stronger affiliation with the clade including the type of the genus.