A Systematic Study On The Genus Paraboea (Gesneriaceae) In China

Paraboea (C. B. Clarke) Ridl. (Epithematinae-Didymocapoideae--Gesneriaceae) comprises ca.130 species distributed to limestone karsts of southern China and Southeast Asia as far south as Sulawesi. Among them,27 species are recorded from southern and southwestern China (e.g. Guangdong, Guangxi, Yunnan, Guizhou), while 18 of them are endemic. In the past decade, almost all researches about Paraboea simply focus on new taxa and new records in China, short of the comprehensive taxonomy revision and general systematic study. In addition, part of the species known only from a single or a handful of localities, the genus was poorly collected and needed further revision.In this study, we sampled 243 individuls of 22 species at the level of population, employed the nuclear internal transcribed spacers (ITS) and chloroplast region (trnL-F spacer, matK. gene, trnH-psbA spacer), and combined the sequences of Paraboea available in GenBank to reconstruct the phylogeny of Paraboea. In addition, we reconstructed the ancestral states of 11 key morphological characters to investigate the relationship of Paraboea in China. Main results and conclusions are as follows:1. Phylogeny of Paraboea in ChinaThe phylogeny of Paraboea based on nuclear ITS sequences which is more effective on the whole resolved the major clades in accordance with the plastid regions. The Paraboea in China is not monophyletic including three scattered clades:(1) the core China Paraboea; (2) Trisepalum birmanicum(Paraboea birmanica); (3) the sister pair of Paraboea hainanensis and Paraboea changjiangensis. The special systematic position of P. hainanensis and P. changjiangensis seperated from the Paraboea species indicates that the genus of Paraboea is polyphyletic. The core China Paraboea are divided into two subclades â…¡and â…¢ based on the two morphological characters with obvious stem or rosulate herb, and widespread distribution or endemism.2. Taxonomic treatment of Paraboea in ChinaA taxomomic treatment of Paraboea in China is presented.27 species are recognized in this region.18 of these species are endemic, and nine are widespread. The new genus Woonyoungiboea is newly described, representing a distinct lineage in molecular studies with the genus Paraboea and close related genera. It includes two species endemic to China (P. hainanensis, P. changjiangensis), distinguished from species of Paraboea by corolla tube long 3-5 mm, no distinct, and without distinguished 2-lipped limb. Paraboea umbellata, Paraboea tribracteata and Paraboea clavisepala are recognized. The morphological complex of Paraboea dictyoneura can be resolved well into four recognized species:P. dictyoneura, P. tribracteata, P. tetrabracteata and P. angustifolia with trival morphological characters.