A Middle Pennsylvanian Basidiomycete Mycelium with Clamp Connections

SUMMARYA fungal mycelium having clamp-connections and chlamydospores has been discovered within the wood of a Middle Pennsylvanian fern. At present the clamp-connection is a structure that occurs only in the Class Basidiomycetes of extant species and is an integral part of the secondary stage of the life cycle. This discovery extends the presence of Basidiomycetes to the middle of the Pennsylvanian Period and illustrates that forms in existence at that time had life cycles comparable to some modern species.