Fifteen species of xylariaceous fungi were isolated from more than 100 Scytinopogon sp. basidiomata in three forests and identified by rDNA ITS sequencing. Xylariaceous fungi were present in the lower part of the basidiomata, occurred less often in the upper part and were absent in the tips of its coralloid basidiomata. These results indicated that xylariaceous fungi grow continuously in the basidiomata and that the apical growth of Scytinopogon sp. basidiomata was faster than the growth of xylariaceous fungi in its host. The results suggested that these xylariaceous fungi established a stable coexistence with Scytinopogon sp. in the forest. Five species of xylariaceous fungi were endophytes in nearby plants. Our study suggested that these endophytic xylariaceous fungi were sources of fungicolous fungi in Scytinopogon sp. in the forest.