A fungal community in plant tissue from the Lower Coal Measures (Langsettian, Lower Pennsylvanian) of Great Britain

Abstract

A diverse assemblage of microfungal remains occurs in periderm cells of a lycophyte from the Lower Coal Measures (Carboniferous) of Great Britain. Among the remains are several types of hyphae, including septate forms with catenulate swellings and small, narrow forms that are multi-branched. There are also several types of spherical structures that differ from one another in size, wall thickness, and ornamentation. The most common of these is interpreted as peronosporomycete oogonia based on specimens with attached antheridia. Other forms may also represent Peronosporomycetes, but might as well belong to the Zygomycota. Oval or tear drop-like structures that occur in clusters or chains are interpreted as conidia. Host reactions in the periderm cells are rare, with the exception of small callosities. Although it is not possible to conclusively identify the (precise) systematic affinities of the fungi, this discovery is significant because it demonstrates that one of the most common plant tissues in the Carboniferous (i.e. lycophyte periderm) provided a suitable habitat for several endophytic organisms at the same time. The overall excellent preservation of the host tissue, together with the evidence of host reactions, indicates that at least some of the endophytes were biotrophic.