Morphological and molecular identification of natural hybridization between Begonia hemsleyana and B. macrotoma

•A natural hybrid of Begonia was found in southern Yunnan of China.•The hybrid between Begonia hemsleyana (♀) and B. macrotoma (♂) was preliminarily identified based on geographic distribution, morphological intermediacy and overlapping flowering time of its parents.•The hypothesis of the natural hybrid was supported by molecular information.•The hybrid is the first generation (F1) and was named as Begonia × dashuigouensis D. K. Tian.

Several plants of a putative hybrid of Begonia were found in southern Yunnan of China during a field survey. They were preliminarily identified as the offspring of a natural hybrid between Begonia hemsleyana as the maternal parent and B. macrotoma as the paternal parent based on the following reasons: the putative hybrid grows sympatrically with B. hemsleyana and B. macrotoma, but more closely to the former; it shows some intermediate morphological characteristics between parents; and the flowering time of parents overlaps, at least partially. Molecular information of internal transcribed spacer (ITS), chloroplast spacer ndhF-rpl32 and SSR markers supported our hypothesis of the natural hybrid between B. hemsleyana (♀) and B. macrotoma (♂). The hybrid should be the first generation (F1) and was named as Begonia × dashuigouensis D.K. Tian based on the name of place where it was discovered.