NUTRITION. 23 



tiated sporophore, of food products collected by a ramifying myce- 

 lium. According to the studies of Harper," Maire,'' and others, there 

 is no sexual fusion in the case of the Basidiomycetes which have been 

 studied. Tayo nuclei are present in the cells of the sporophore, but 

 these are associated conjugate nuclei, and the fusion of these in the 

 basidium is generally considered in no sense an act of fertilization, 

 but rather a form of nuclear reduction. Maire states that the cells of 

 the mycelium obtained by the germination of the basidiospore are 

 uninucleate. It has not yet been ascertained when or how the binu- 

 cleate condition arises. 



NUTRITION. 



Although Agaricus eampestris has been cultivated for so long a 

 time, it does not seem that it has previously been subjected to careful 

 experimentation from the point of view of nutrition. The belief 

 generally prevalent is that the most essential factor in the nutrition 

 of the mushroom is the " ammonia " of the manure or compost. 

 Again, it is claimed that organic Avaste products, such as those indi- 

 cated, must undergo a process of fermentation, or " preparation," 

 in order to furnish the necessary nutrients for the growing mycelium. 

 This idea, as will be seen later, is merely based upon casual observa- 

 tions " in nature," and it is found wholly erroneous when tested for 

 its fundamental worth by the elimination of other factors of the com- 

 post environment. 



Growth on manure and other complex media. — Early in this inves- 

 tigation it was ascertained that the mycelium of Agaricus eampestris 

 in pure cultures would grow luxuriantly on fresh stable manure, and 

 as a rule upon the same product in any stage of fermentation or 

 decomposition. In some instances, undoubtedly, fresh manure may 

 contain injurious compounds; somewhat oftener the same is true for 

 the fermented product. In some instances it is desirable to dry or 

 thoroughly air the fresh manure before use. Fresh manure from 

 grass-fed animals is not to be recommended. The mycelium also 

 grows luxuriantly on bean stems or pods, on half-rotted leaves of 

 deciduous trees, on rich soil, on well-rotted sawdust, and on a variety 

 of other substances. It does not grow readily upon peaty products. 



Some of the more promising edible species were cultivated in 

 various media in order to obtain an idea of the comparative value of 

 these media in furnishing a nutrient to particular forms. It is not 

 possible, of course, to base definite conclusions upon results obtained 



« Harper, R. A. Binucleate cells in certain Ilymenomycetes. Bot. Gaz., 

 83: 1-2.3. 1902. 



^ INIaire, R. Recherches cytologiques et taxonomiqiies sur les Basidiomycetes. 

 Bui. Soc. Myc. de France, 18 : 1-209. 1902. 



