The genus Begonia (Begoniaceae), comprising approximately 2200 species, is is one of the largest angiosperm genera and is widely distributed across tropical and subtropical regions worldwide. The karst region of Guangxi is recognized as a hot spot for the Begonia section Coelocentrum, a group characterized by rhizomatous habits, four tepals in staminate flowers, three in pistillate flowers, and typically one-locular ovaries with parietal placentation.
During their filed surveys in southwestern Guangxi, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences collected two unknown Begonia taxa from karst habitats in Debao County and Tianyang District, Baise City, respectively. After careful morphological studies, they confirmed the two species were new to science. The two species were named Begonia renkunii and Begonia tianyangensis respectively and published in Phytotaxa.
Begonia renkuni is a perennial rhizomatous herb with creeping rhizomes reaching up to 60 cm long. Its leaves are narrowly ovate, asymmetrical, and sparsely setulose above with dense red villous hairs along the veins beneath. The species is named in honor of Mr. LI Renkun, who contributed to begonia resource investigation in China and was the first to discover the species.
With fewer than 50 mature individuals known from a single population and some plants dying from drought, the species has been assessed as Critically Endangered (CR) under IUCN criteria.
Begonia tianyangensis is morphologically similar to Begonia rhytidophylla but can be distinguished by its elongated rhizomes and internodes, shorter and wider stipules, denticulate leaf margins with short cilia, 7–8 primary veins, and smaller pistillate flowers and capsules.Two populations with an estimated 500–1,000 mature individuals are known. The species has been assessed as Endangered (EN).
In addition, the researchers examined the type specimens of Begonia fangchengensis and Begonia shaoqingii and concluded that the two names refer to the same species. Begonia fangchengensis is therefore reduced to a synonym under Begonia shaoqingii, which remains classified as Endangered (EN).
Begonia tianyangensis (Image by LI Renkun)
Begonia renkunii (Image by LI Renkun)
Published: 4 September 2026
