252 PRINCIPLES OF SOIL MICROBIOLOGY 



C. FUNGI IMPERFECTA no sexual spore formation known. 



I. HYPHOMYCETES. 62 Hyphae septate, hyaline or dark colored, 

 separated from one another or united into coremia. Conidia 

 formed either as oidia, by the breaking up of hyphae, or are formed 

 on little differentiated branches of the mycelium or on special 

 conidiophores. The latter are simple or much branched. The 

 order is divided into 4 families, according to shape of conidio- 

 phore and structure of mycelium. 



1. Conidia produced on single conidiophores, more seldom in 

 the form of oidia. Vegetative hyphae as well as conidia and 

 conidophores hyaline, pale or light colored, not dark, Mucedi- 

 naceae Link: 

 1'. Spores one-celled: 



I". Conidiophores never sharply differentiated from 

 mycelium, sometimes lacking; conidia may de- 

 velop by the breaking up of hyphae into oidia: 

 1'". Conidia oval or spherical, never spindle- 

 shaped : 



(a) Conidiophores very short, hardly distin- 

 guished from the mycelium: 



(a') Conidia produced on short side branches 



singly or one after another, Myceliophthora. 



Isolated from the soil by Goddard. 

 (b') Conidia large, with a thick membrane, 



Coccospora. Isolated from the soil by 



Goddard. 



(b) Conidia developing as oidia by the breaking 

 up of hyphae or as chains on short, not sharply 

 differentiated branches, Oidium (Oospora). 

 Isolated frequently from the soil. 



(c) Conidia on definite branches; mycelium 

 usually well developed and compact, Monilia 

 (No. 99, PI. XIV). Various species of 

 Monilia have been isolated from the soil. 



2"'. Conidiophores well defined, erect, short; 

 conidia in chains, short cylindrical, truncate 

 at both ends, Geotrichum. Seldom found in 

 the soil. 

 2". Conidiophores sharply differentiated from the my- 

 celium: 



62 In the study of this group of fungi the system used by Lindau (Fungi im- 

 perfecti: Hyphomycetes. Rabenhorst's Krypt. Flora, Abt. 8 and 9. 1907- 

 1910) has been followed. This work as well as that of Engler, A., and Prantl, K. 

 (Die naturlichen Pflanzenfamilien. Leipzig. 1897-1907) will be found to be of 

 great assistance in the identification of most representatives of the Hyphomy- 

 cetes, except in the case of the genera Aspergillus, Penicillium and Fusarium, 

 where special monographs are available. 



