XVI International Botanical Congess

The genus Begonia in Taiwan is characterized by a high level of endemism and morphological polymorphisms. We have used genetic variation of nucleotide sequences of both trnD-trnT noncoding spacer (cpDNA) and nrDNA ITS to reconstruct the phylogeny of species of Begonia. Low level of genetic polymorphisms of cpDNA was detected between species, whereas remarkably high genetic variation of nrITS was detected both within and between species. The organelle tree recovered by PAUP invalidates monophyly of several species of Begonia. The ITS tree also reveals multiple origins of a number of endemic taxa. Such data suggest that frequent hybridization (often unidirectional) and introgression played a role in the speciation of plants of Begonia in Taiwan.