Abstract:The genus Trigonobalanus (Fagaceae) includes 3 species, T. verticillata from the Celebes, Borneo and Malaya, T. doichangensis from northern Thailand and southern Yunnan (China), and T. excelsa from Colombia in South America. The genus is spread geographically across the two hemispheres which makes it attractive for taxonomic and phylogenic studies. The name T. doichangensis, is used in this paper although recent studies have suggested that the 3 species are so isolated from each other that they should be t...