Abstract
A new species Astilbe uljinensis B.U.Oh & H.J.Choi is described from Gangwon-do and Kyeongsangbuk-do in South Korea based on its morphological characteristics and distributional pattern. A. uljinensis is easily distinguished not only from three other Astilbe species in South Korea, but all other species in the genus by possessing a green young rachis, dense long whitish glandular hairs on the young rachis, dense long brownish glandular hairs on the mature inflorescence, and a slightly undulated margin of leaf epidermal cells. Specific comparisons of morphological features such as the type of the trichome, the shape of the leaf epidermis cell, and the color of the young rachis that differentiate A. uljinensis from Astilbe chinensis, another South Korean Astilbe species, are provided.