New records of two alien plants, Carex annectens and C. gravida (Cyperaceae) in Korea

In Korea, two alien plants were newly found, and we describe their morphological characteristics and habitats with photographs. One, a member of Cyperaceae, Carex annectens, was found in roadside forests from Gyeongsangnam-do. This species can be distinguished from C. gravida by having inflorescences, usually branched, with more than 15 spikes and pistillate scale yellow or brown. The other is C. gravida, which was found along roadsides of open habitats from Chungcheongnam-do and Gyeonggi-do. This species can be distinguished from C. muehlenbergii Schkuhr ex Willd. var. enervis Boott by having proximal leaf sheaths longitudinally green-and-white striped and with prominent green cross veins. These species grow on roadsides, suggesting that they were likely to have been introduced when green sites were installed and during road construction. Their introduction into Japan has been reported, but the associated ecological risk is unknown. Therefore, we need continuous population monitoring for these new invasive species in Korea.