Soil Fungi 83 



species and in the Ireciuenc) ot occurrence, are 7Aj<:,oihijiichus, Mu- 

 cor, Rhizopus, PcnicilUum, Aspergillus, frichodenna, Fusarium, and 

 Clodosporiuni. The wide distribution of different genera of fungi 

 in the soil is demonstrated in Table 13. Brierley tabulated sys- 



T.xni.K l.'{. Isolation- ok Common Gknera of Soil Fungi ky Dikkkkent 

 Investigators (from Waksiuan) 



Mclycan 

 and 



Genus Koiiing Dale Jensen Goddard Wilson Waksman 



Acrosialagimts * * * . . * 



Alternaria * * * * * 



Aspergillus * * * * * * 



Cephalosporium * . . . . . . . . * 



Cladosporium . . * * * * * 



Fusarium * . . * . . * 



Mucor * * * * * * 



Pejiicillium * * * * * * 



Rhizopus .. * * * * * 



Trichodcrma * * * * * * 



Verticillium . . * . . * . . * 



Zygorhynchus . . * * . . * * 



* Found to be present. 



tematically all the fungi which have been found in the soil. Of these, 

 56 species belonged to 11 genera of Phycomycetes; 12 species be- 

 longed to 8 genera of Ascomycetes; 197 species belonged to 62 

 genera of Fungi Imperfecti. Many more groups have since been 

 added from all parts of the world. Niethammer and Gilman pub- 

 lished comprehensive summaries of the fungi isolated from various 

 soils. 



When fresh plant materials are added to the soil, the fungus popu- 

 lation is greatly stimulated. There is usually a sequence of forms, 

 depending on the chemical composition of the materials and the 

 extent of their decomposition. On the basis of their relation to or- 

 ganic matter, the fungi were divided into seven groups: (1) humi- 

 coloiis forms, which grow on practically pure humus; (2) terrestrial 

 (geophilic, terricolous) forms, which grow in soil containing more 

 or less organic matter; (3) coprophilic (fimicolous) forms, growing 

 on manure; (4) hijpogeous forms, which grow below the surface of 

 the soil; (5) lignicoleous forms, growing on the lignins of plant ma- 

 terials; (6) pseudoparasitic forms, which are wound parasites, 

 mycorrhiza-formers, facultative parasites; and (7) true parasites. 



