Flora and Geographical Distribution of the Wild Lycophytes and Ferns in Haitan Island and Surrounding Islands

Through field surveys and data compilation, statistical analysis of the lycophytes and ferns floristic composition, distribution area types and ecological types of Haitan Island and the surrounding 24 islands, and compared with the distribution area types in different regions, it is expected to provide a reference for the rational development and utilization of plant resources in Haitan Island and the surrounding islands, the results show that Haitan Island and its surrounding islands share 20 families, 37 genera and 60 species of stone pines and ferns. In the floristic,there are both primitive families and evolutionary families, as well as families in between. The origin of the flora in this area is ancient; Most of the genera are single species, the dominant family genera phenomenon is not obvious; The areal type of the main islands in Haitan Island and the surrounding islands is dominated by tropical distribution, with significant tropical relatives and the transition from tropical to temperate; Haitan Island and its surrounding islands have a higher similarity and close relationship with Dayushan Island and Dongshan Island, which are close in latitude, and have lower similarity with Changdao Islands, which are farther in latitude; In terms of geographical relationship, the region is closer to the south subtropical mountains, while Haitan Island and surrounding islands are the most closely connected with the Guanyintong Nature Reserve, which has a strong tropical character; In terms of ecological type, the lycophytes and ferns in this area are mainly soil and stone. Besides, Haitan Island and its surrounding islands are home to Ceratopteris thalictroides(VU, level Ⅱ), Cibotium barometz(level Ⅱ), and endemic species to China Selaginella uncinata. The research results can provide a theoretical basis for rational utilization and protection of the plant in Haitan Island and its surrounding islands.