The Fungi in Cordaitean Rootlets

In a recent unpublished study of petrified cordaitean fossils from the American Pennsylvanian, I was unable to find any fungi infecting the rootlets, although mycorhizas have been reported in European cordaitean rootlets (Lignier, 1906; Osborn, 1909; Halket, 1930; Zimmermann, 1933). The absence of fungi in the American rootlets led me to reexamine most specimens supposed to contain mycorhizas, and I find that although fungi are sometimes present, they are by no means constant in occurrence. It seems most likely that they are parasites or saprophytes and not symbionts. As the mycorhizal nature of these fungi is usually accepted by mycologists (e.g., AVolf and Wolf, 1947, p. 487; Kelley, 1950, p. 51), the following re-examination of the evidence is presented.