FOSSIL PLANTS/Fungi and Lichens 439 Figure (A) Prototaxites; transverse section showing the internal anatomy, which is entirely constructed of interwoven septate tubules (?hyphae); scale bar: 100 mm (B) Parasitic Chytridiomycetes on a spore of the Rhynie Chert plant Aglaophyton major ; scale bar: 10 mm (From Taylor TN, Remy W, and Hass H (1992) Fungi from the Lower Devonian Rhynie Chert: Chytridiomycetes American Journal of Botany 79: 1233 1241.) (C) Radial section of Callixylon newberryi (progymnospermous wood) from the Upper Devonian of Indiana, showing branching fungal hyphae in one of the tracheids; scale bar: 35 mm (D) Traquairia williamsonii, an ornamented sporocarp from the Upper Carboniferous of Kentucky, containing several thin walled spores; scale bar: 80 mm (Adapted from Stubblefield S and Taylor TN (1983) Studies of Paleozoic fungi.1 The structure and organization of Traquairia (Astomycota) American Journal of Botany: 70: 387 399.) (E) Cross section through an Araucarioxylon (gymnospermous wood) stem from the Triassic of Antarctica, showing numerous pockets of decay (lighter areas); scale bar: 1.2 cm (From Stubblefield S and Taylor TN (1986) Wood decay in silicified gymnosperms from Antarctica Botanical Gazette 147: 116 125.) (F) Leaf colonizing fungus on an angiosperm leaf from the Eocene (Tertiary) of the USA; scale bar: 60 mm (G) Geotrichites glaesarius, a saprophytic fungus from the surface of a spider that is preserved in Tertiary amber from the Dominican Republic; scale bar: 60 mm (e.g Figure 2C), some possessing rounded knobs (socalled clamp-connections), and spores; indirect evidence of the presence of these fungi includes solution troughs along the inner surfaces of water-conducting cell walls Because modern basidiomycetes are the primary degrading agents of lignin and cellulose, dissolution patterns in fossil wood that resemble those seen in modern wood indicate the existence