106 TEXT-BOOK OF FUNGI 



diameter, and weighs four pounds in the dry condition. 

 Many kinds of small sclerotia are formed in the tissues of 

 plants that have been attacked by the fungus producing 

 the sclerotia, and in the case of parasitic species, the 

 primary infection of a crop is often due to the presence of 

 sclerotia that have been carried with manure to the land. 

 De Bary gives a detailed account of the structure of 

 sclerotia, also of rhizomorphs, which functionally agree 

 with sclerotia, from which they differ in assuming an 

 elongated, cord-like form. The long, black, anastomosing 

 rhizomorphs of Agaricus melleus are well known. 



Both sclerotia and rhizomorphs were at one time 

 considered as true species, and called Sderotium and 

 Rhizomphora respectively. 



Buds or gemmae are formed under certain conditions 

 of growth of the mycelium of various species belonging 

 to the Mucorineae and others. Portions of hyphae or 

 conidiophores rich in protoplasm become divided into 

 short cells by the formation of cross-walls ; such cells 

 often become thick-walled, enter into a resting-stage, and 

 afterwards produce ordinary mycelium. In other instances 

 the walls of. these modified hyphal cells remain thin, and 

 reproduce themselves by budding from all parts of the 

 surface, after the fashion of yeasts or Saccharomyces. Such 

 buds give origin to mycelium and produce the typical 

 fruit of the species from which they originated, when 

 placed under favourable conditions. 



When these budding forms of Mucor are produced in 

 abundance, they possess the power of setting up alcoholic 

 fermentation, and this fact led to the erroneous belief that 

 the Saccharomyces were not entities, but produced under 

 certain conditions by Mucors and other fungi. 



