Well-preserved fossil mycelium consisting of clamp-bearing septate hyphae and chlamydospores are recorded in a structurally preserved cycad trtmk from the Lower Triassic of Inner Mongolia,NE China.A large amount of fungal hyphae are observed in the host tissues,and are can be divided into two types.One of them,with relatively wider diameter of 2.0-3.0 μm,is tubular in shape with septa and typical clamp-connection.Hyphae are branched with a right angle or not.