XVI International Botanical Congess

Permineralized Cordaites wood from three Late Carboniferous coals contains fossils of three fungal groups. Hyphae bearing ovoid bodies (4 - 13 ?m diameter) with double walls, pores, cleavage furrows, and diclinous antheridia, occur in ray cells. These fungi may be oomycetes, however, extant oomycetes are rare in wood and the fossil forms are smaller than most extant forms. Large (3 - 5 ?m diameter) hyphae in ray cells and tracheid lumena probably derive from stain fungi. Spores of the extant stain fungus, Alternaria, co-occur with these hyphae, extending its range from the Tertiary to the Late Carboniferous. Narrow hyphae (1 - 2?m diameter) associated with the walls of tracheids or the spaces between tracheids are probably decay fungi, either basidiomycetes or xylariaceous ascomycetes. Most Late Carboniferous Cordaites wood displays evidence of decomposition by lignolytic and cellulytic decay fungi.