Kelley — 48 — Mycotrophy 



in cultivated and probably other soils, forming mycorrhizal associa- 

 tions in the roots of many flowering plants and cryptogams, including 

 prothalli of liverworts and some ferns." After describing these 

 fungi, he notes the "fossil records" of fungi "of this type". Thus 

 KiDSTON and Lange found a fungus, Palaeomyces Asteroxyli, very 

 regularly in inner cortex of Asferoxylon Mackeii and of basal region 

 of stems having transitional structure between rhizome and stem, 

 all from Rhynie Chert assigned to Early Devonian. It is not 

 clear that evidence is afforded of any mycorrhizal structure in this 

 fossil material, and we may note that Palaeomyces Gordonii is found 

 on decaying stem of Rhynia major. Butler cites still further the 

 Protomycitis protogens described by Smith in 1884 from rootlets 

 of Lepidodendron, assigned to Lower Coal Measures of Yorkshire; 

 but again we do not know that there is positive evidence for consider- 

 ing this material mycorrhizal. Seward says that Peronosporites 

 antiquarius is found in scalariform tracheids of Lepidodendron from 

 Coal Measures. The supposed reproductive bodies may be oogonia or 

 sporangia, or merely vesicular enlargements of hyphae. Similar 

 swellings are seen in cells, probably of cortex of Lepidodendron or 

 Stigmaria, from the Halifax Coal Measures. Such material would 

 be questionably assigned to mycorrhizae. 



Still more recent material comes from peat bogs, locally known 

 as "muskegs", in Alberta through Prof. Lewis of Edmonton; but 

 here again there is no positive evidence of a mycorrhizal nature. 

 Butler (1939) described this interesting material and decided that 

 the fungus is the same as the "well-known vesicular-arbuscular 

 endophyte of modern plants and with the fungus described by 

 OsBORN and Halket". Again, Rosendahl (1943) reports the same 

 sort of fungus from three Pleistocene sites in Minnesota and refers 

 the fungus to the genus Rhisophagiis. The fossils came from a depth 

 of more than 80 feet in well-borings, and after sand was washed 

 from the matrix the material was examined. From the excellent 

 photographs, one would think that he was looking at mould fungi; 

 and it is stated in the paper that the fossil fungi had grown on moss 

 leaves and coniferous needles, which are scarcely the organs in which 

 one would naturally look for mycorrhizal fungi. Incidentally, it may 

 be mentioned that according to Ellis (1917) there are 15 species of 

 fossil Phycomycetes known, and of these he mentions Paleomyces 

 hacilloides as a saprophyte on fossil leaf mould. 



Fossil Hepatics: — So far as we are aware, there is no record 

 of fossil endophytes in hepatics. It would doubtless be a difficult 

 study of a rare specimen were fossil mycothalli to be described. 



