PHYCOMYCETES 253 



animal matter, dung, etc. ; some are incipient parasites on 

 ripe fruit, etc., whereas some species of Rhizopus are 

 destructive parasites. 



Chaetocladieae 



Growing on dung. Distinguished by the much-branched 

 sporophore; all the main and secondary branches are 

 sterile and end in spine-like points. Sporangia small, 

 globose, usually warted, containing only one spore, spring- 

 ing in small clusters from short, lateral, ternary branchlets. 



Chaetodadium Jonesii and C. Brefeldii, both British 

 species, are not uncommon on dung, often mixed with 

 Mucor mucedo, on which they are considered to be 

 parasitic. 



Mortierelleae 



Mycelium slender, dichotomously branched and fre- 

 quently anastomosing. Sporangiophores erect, often pro- 

 duced in small clusters, swollen at the base and tapering 

 upwards, simple or branched, each branch terminated by 

 a globose, polysporous sporangium without a columella. 



In Mortierella, the only British genus, the branches of 

 the sporophore are often arranged in a verticillate or 

 corymbose manner. 



Growing on decaying organic substances, fungi, wood, 

 dung, etc. 



Syncephalideae 



Growing on dung, decaying organic substances, etc. 

 Distinguished at once by the numerous cylindrical or 

 slightly clavate sporangia springing from a swollen head, 

 borne at the tip of an elongated stem. 



Each sporangium containing a single row of spores, or 



