Fig. 1

Guangxi’s limestone karsts (a–d) and habitats of Begonia luzhaiensis (e–h). a The picturesque limestone fengcong karst (Waltham 2008) along the Li River in Guangxi, China is a habitat for many limestone plants, including B. luzhaiensis. b Aerial photography taken before descending into Guilin Airport, Guangxi, showing the fragmented and cockpit-like karst landscape. c The entrance of a limestone cave in Luzhai County, Guangxi where the LZ population (Fig. 2) was sampled. This cave is also the type locality of one rare gesneriad, Chirita luzhaiensis (≡ Primulina luzhaiensis) (Huang et al. 2010). d Rice terraces in Tian’e County, Guangxi, showing the typical agricultural practices in the region and degraded limestone forest in a limestone karst. e B. luzhaiensis grows in the limestone cave (Fig. 1c) in Luzhai County (LZ in Fig. 2). f B. luzhaiensis grows on a limestone outcrop in Xincheng (XC in Fig. 2). g B. luzhaiensis grows in the entrance of a limestone cave in Rongshui County (RS in Fig. 2). h B. luzhaiensis grows on the base of a limestone tower along the Li River (YS in Fig. 2)