Abstract: To explore species diversity of myxomycetes in tropical forest ecosystems in China, the Huanglian Mountain National Nature Reserve of Yunnan Province was set as a sample for investigation of composition and abundance of the myxomycetes therein. From samples of barks and ground substances, collected from the reserve and incubated in a moist chamber, a total of 47 species of myxomycete, belonging to 16 genera of 8 families in 6 orders, were obtained, Arcyria cinerea was the most dominant species with relative abundance reaching 18.07%. From the ground substances 45 species were harvested and 38 from the barks, which obviously indicates that the ground substances are higher than the barks in myxomycetes species richness. Myxomycetes on the ground substrates were 4.81±0.65 in species diversity index and myxomycetes on the barks were 4.59±0.03, of which the difference is not significant（P＞0.05）. All these indicate that myxomycetes in the Huanglian Mountain Nature Reserve do not have any preference for substrate types. Species diversity index of myxomycetes also varied with season, from wet-season (3.78±0.05) to dry-season (4.58±0.02), and the difference was significant（P＜0.05）, which indicates that substrates collected in dry-season had more myxomycete spores. The total species diversity index of the myxomycete in the Huanglian Mountain was 4.96, higher than those reported in tropical nature reserves in the other parts of the world, which indicates that the tropical forest ecosystem in China possesses a rich store of myxomycetes resources.

Key words: myxomycete, species composition, abundance, the northern tropics