Several morphological and palynological characteristics—including petiole length, number of anthers, calyx persistence, presence of petaloid sepals, morphology of keel appendages, fruits, seed appendages, and shapes and polarity of pollen—were observed in this study. Five genera and nine species of the family Polygalaceae are recognized in Taiwan, including one new combination, Heterosamara arcuata (Hayata) J.Y. Wu & T.Y.A. Yang, comb. nov. Keys to the genera and species, taxonomic descriptions, tables summarizing characteristics, and photographs of each taxon are also provided.