Two new species of Primulina (Gesneriaceae) from limestone karsts of China.

Xin Hong,Zhong-Lin Li,Wei-Hua Qin,Shou-Biao Zhou,Jia-Zhi Liu,Fang Wen

doi:10.7717/peerj.4946

Abstract

The limestone karst area of South China is a major biodiversity hotspot of global terrestrial biomes. During extensive field work on the Guangxi limestone formations, two unknown species of Gesneriaceae were collected. After conducting a comprehensive study of the literature and herbarium specimens, Primulina davidioides and P. hiemalis are recognized as two species new to science, and described and illustrated here. P. davidioides is morphologically close to P. lunglinensis based on the shape of the leaf and flower, but it can be easily distinguished by the shape of the bracts, corolla and stigma, indumentum of peduncles, pedicels and pistil and number of staminodes. P. hiemalis is closely relate to P. luzhaiensis in vegetative appearance, but differs in the shape of the calyx and stigma, number of bracts and staminodes, indumentum of the leaf blade and peduncle, and position of stamens in the corolla tube. Considering that not enough is known about their populations, it is proposed that their conservation statuses should currently be classed as data deficient (DD) according to the IUCN Red List Category and Criteria.

Highlights

The tropical and subtropical karst landforms of southern and southwestern China are renowned because of their unrivalled biodiversity and high endemism among the tropical and subtropical floras of the world (Myers et al, 2000; Clements et al, 2006; Hou et al, 2010)
During our continuous floristic surveys of limestone karsts flora in 2009 and 2010, we revealed an additional two species of Primulina not previously known
The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Code of Nomenclature for algae, fungi, and plants (ICN), the new names contained in the electronic version are effectively published under that Code from the electronic edition alone

Summary

Introduction

The tropical and subtropical karst landforms of southern and southwestern China are renowned because of their unrivalled biodiversity and high endemism among the tropical and subtropical floras of the world (Myers et al, 2000; Clements et al, 2006; Hou et al, 2010). A great number of new species were described in the genus Primulina (Gesneriaceae) in recent years (Yang et al, 2018), and it is becoming one of the most interesting genera of the Old World Gesneriaceae, comprising more than 170 species (Wang et al, 2011; Möller et al, 2011; Möller et al, 2016) This group shows high levels of endemism and ecological specialisation (Gao et al, 2015), with narrow island distributions (Wang et al, 1998; Li & Wang, 2004; Wei et al, 2010), i.e., only in karst towers and caves (Ai et al, 2015). Many Primulina species pairs can successfully interbreed through artificial experiments (Wen, 2008; Zhang, Yang & Kang, 2017), suggesting that Primulina is probably a genus under recent or ongoing speciation and differentiation (Gao et al, 2015)

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