ENVIRONMENTAL FACTORS 



75 



Solutions. It has been the general experience that the readily 

 culturable parasitic and hemiparasitic fungi have about the same 

 relation to strengths of solu- 

 tions as the saprophytic forms. 

 Ordinarily, therefore, such 

 forms give abundant growth 

 under widely different condi- 

 tions of concentration of the 

 substratum. According to 

 Eschenhagen the concentra- 

 tions at which Botrytis cinerea 

 may grow under ordinary cir- 

 cumstances are as follows : 

 grape sugar, 5 1 per cent ; 

 cane sugar, 37 per cent ; 

 sodium nitrate and calcium 

 chloride, 16 per cent; sodium 

 chloride, 12 per cent. In the 

 culture work in the laboratory 

 it will be found, however, that 

 differences in the Strength of Fig. 15. Cells op Ericaceae (after Ter- 

 the culture medium will be netz), and Orchidace.-e with Endophytic 

 accompanied by noticeable Mycorhiza - als ° Coralloid Roots 

 differences in the form of the fungous colony, amount of the 

 mycelium, and the character of the spores produced. 



