We report two newly naturalized species-Astraea lobata (L.) Klotzsch and Merremia umbellata (L.) Hallier f. subsp. umbellata in Taiwan. Astraea was a newly recorded genus to the flora of Taiwan and A. lobata was its type species. This species was characterized by its tri-lobed leaves and highly divided styles. In addition, on the reviewing of literature and specimen of Taiwanese Merremia, M. umbellata was recorded by some authors. The only specimen cited by some of them, was contained only one leaf that hardly to recognized as any Merremia species. Besides, the description of this species was more or less scanty in those studies. Thus, this study confirms the newly naturalization of M. umbellata in Taiwan. Descriptions and photos of two species are provided.