Cytological Study of Begonia Sect. Platycentrum (Begoniaceae) with Chromosome Number 2n=22

Previous chromosome information for Asian Begonia sect. Platycentrum with 2n=22 is restricted to 28 taxa. Here we add another 23 species to the list and reconfirm this chromosome number for nine species of sect. Platycentrum. The number of species of sect. Platycentrum with 2n=22 reported is increased to 51 taxa, covering ca. 70.8% of the 72 taxa with reported chromosome numbers in the section. Additionally, we provide the first report of karyotypes of 32 species with 2n= 22 of the section. Based on the present results and previous chromosome reports for a total of 51 taxa with 2n= 22, the chromosome evolution for 2n= 22 in sect. Platycentrum is discussed.