New records of four introduced alien plants in coastal and port areas of South Korea

We report the first confirmed records of four alien plants belonging to the families Poaceae, Cyperaceae, and Fabaceae in South Korea. Bromus rubens L. originated in the Mediterranean area and adjacent regions and was first discovered in the port area of Gunsan-si. This species is known as an invasive species in the Americas, Australia, parts of Europe, Japan, and Africa and is designated as an Alert Alien Species in Korea. Eriochloa contracta Hitchc., native to the United States, is classified as a weed harmful to crops and has been identified in an open area near the coast of Geoje-si. Carex oklahomensis Mack., which is indigenous to the central and eastern United States, was first identified in Sacheon-si, appearing to be the first recorded appearance in Asia. Finally, Chamaecrista nictitans (L.) Moench., a plant native to the Americas and introduced to Japan, was identified for the first time in Tongyeong-si. This study presents the distribution of introduced alien plants in Korea and provides information on their habitats and morphological details, accompanied with photographs. Additionally, this study establishes an important baseline for enhancing knowledge regarding alien plants primarily introduced through ports and coastal areas.