Notes on section in Hainan Island, China.

Hainan is the second largest island in China with the most extensive and well-preserved tropical forests and is also the largest island of the Indo Burma Biodiversity Hotspot. It provides conservation for the unique ecosystem of the island. Recent studies have shown that there are diverse fungal species in Hainan. In this study, about 40 collections of the genus have been studied based on the morphology and molecular systematics, including 35 Chinese specimens (24 from Hainan, and eleven from other regions) and three specimens from other countries (Singapore and Malaysia). In total, five new species belonging to section are described: , , , , and is recorded for the first time in Hainan. It is also the first report of this fungus occurring, outside Yunnan Province, China. Among the five new species, two are unique in this section because of the appendiculate pileus margin and the absence of an annulus. Based on these new findings, the diagnosis of the section should be slightly modified to include a few species with appendiculate margin and the lack of annulus.