October, 19C6] 



Mycological Bulletin Nos. 67 and 68 



269 



Fig. 21)8. A \oun.e Specimen cf the Common Puffball (Calvatia craniformis). 

 From Bulletin No. 85, B. M. Duggar, Bureau of Plant Industry, U. S. 

 Department of Agriculture. 



pure cultures of desirable edible species, particular]}- of those species 

 the spores of which could not be o1)tained pure or which could not be 

 readily germinated. , 



During the two subsequent seasons this method has been employed 

 with a great variety of furgi representing many natural orders. No 

 systematic endeavor has been made to determire the limitations of the 

 tissue-culture method as applied to Basidiomycetes, but. incidental to the 

 general studies, cultures have been made from forms differing very 

 widely, not only in relationship but also in texture and in habitat. 



Temper.vture .\nd MoisTfKE. — The temperature factor is, next to that 

 of good sp:iwn, perhaps the most important in mushroom growing. It has 

 been frequently stated that mushrcom growing is not profitable when the 

 temperature niav not be maintaired more or less continuously at from 50° 

 to 60° F. It is very probable that the exact temoerature which may be 

 corsidered an optimum will vary somewhat in different sections of the 

 country. It will be noted later in detail that the temperature factor acts 

 not so directly upon the growth of the spawn or the production of 

 mushrooms as indirectly to render some other conditions of the environ- 

 ment injurious. It is best to consider that in practice the optimum tem- 

 perature for mushroom growing varies from .".3° to r)S° F. 



VARi.\Bn,iTY IN [Mushrooms Grown under Different Conditions. — 



