FOSSIL MYCORRHIZAE 481 



5. Stilbaceae 

 Stilbites coniventzi Felix is among the coremioid species. 



6. Tuberculariaceae 



On Tertiary wood occurs a form identified as Spegazzinites 

 cruciformis Felix. 



At the end of his list of classified fossils Pia has assembled a 

 group that does not fit among present-dav genera, and therefore, 

 their classification is uncertain. This list includes Palaeomyces 

 gordoni Kidst., P. majus Ren., Fnngites jenensis Hallier on mussels, 

 Xylomites polaris Heer from the upper Triassic, X. zamitae Gopp. 

 from the Carboniferous, Caenomyces sapotae Berry from the 

 Eocene, Nyctomyces entoxy linns Ung., Anthracomyces cannal- 

 lensis Ren., A. rochei Ren., Sclerotites brandonianiis JefTr. et 

 Chrvsl. in Tertiary lignite, Phellomyces dnbhis Ren., Rhizomor- 

 phites intertextns Sternb., and R. polymorphic Matth. 



FOSSIL MYCORRHIZAE 



Seward (1933) expressed the opinion, "From very early times 

 there have been two kinds of associations between higher plants 

 and fungi: fungi preying upon their hosts and others beneficial 

 to the hosts in which they lived." In the beneficial category are 

 the mycorrhizal associates. It is exceedingly interesting that this 

 peculiar symbiotic relationship extends so far into antiquity as 

 the lower Coal-Measures period. Some appreciation of the my- 

 corrhizal habit can be obtained from the accounts of Weiss (1904), 

 Lignier (1906), and Osborn (1909). Weiss (1904) observed my- 

 corrhizae in coal balls. He says of them, "The excellent preserva- 

 tion of both the fungus and the host and the specialization of the 

 cortex into two layers comparable. with similar structures in recent 

 mycorrhizae suggest that, as in the case of the latter, the host 

 plant is deriving some benefit from the presence of the fungus." 

 Lignier (1906) identified the fungal component on some Sequoia- 

 like tree root as Radicidites reticidatns. The mycorrhizae ob- 

 served by Osborn (1909) involved the roots of Amyelon rad'icans. 



