LAUSR

Abstract A new species Impatienshambaeksanensis from Gangwon-do, South Korea, is described and illustrated, based on its morphology and distribution. I.hambaeksanensis is different from I.furcillata, another similar Impatiens species in South Korea, in some ways: I.hambaeksanensis possesses a serrate leaf margin with flat tooth tip, while I.furcillata possesses a crenate leaf margin with erect tooth tip; it has an erect inflorescence, while I.furcillata has a pendulous inflorescence; it has a smaller flower which is 2–2.6 cm long, while I.furcillata has a flower of 2.3–3.2 cm; the flower is white or pinkish-white with yellowish and purplish spots, while I.furcillata has a white lower sepal and pinkish-white lateral united petals with yellowish spots; the distal part of the lower sepal is mostly not coiled or rarely 1-coiled, while that of I.furcillata is never coiled; the spur tip is expanded, round and slightly biparted, while that of I.furcillata is expanded, ellipsoidal and clearly biparted. A taxonomic description, a holotype and photos of morphological characteristics of the new species are provided. A table which includes the morphological comparison and a geographical distribution map are presented as well.