[Vol. 6, 1919] 



142 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



although the P n values of the solutions with the di- and tri- 

 basic potassium phosphates were originally greater than with 

 the monobasic phosphate the lowering due to growth was very 

 pronounced. This difference in the shifting of the active 

 acidity due to growth in Reed's and Richards' solutions may 

 be attributed to the fact that in Reed's solution the citrate 

 radical of the sodium citrate acts as the source of carbon, thus 

 liberating alkaline sodium compounds. 















Conclusions 



1. Many wood-destroying fungi are not suitable for growth 

 experiments with liquid media. 



2 



With respect to the media employed and to the 



studied, Merulius pinastri, Polyporus lucidus, Polystictus v 

 sicolor, Pleurotus sapidus, and Trametes Peckii grow best 



the order named. Others 



7 



media 



e. g., Lenzites vialis, Daedalea quercina, and Merulius lacry- 

 mans on Richards ' solution. 



i 



3. Czapek's solution with the monobasic, and Richards' so- 

 lution with the mono-, di-, and tribasic potassium phosphate 

 proved generally to be suitable media. Thus, there is a de- 

 cided indication of the desirability of selecting a specific me- 

 dium for each fungus. 



4 



In the solutions studied the H ion concentration does not 



seem to be the limiting factor in growth, nor in general does 

 it appear to be the factor (within the limits studied) which de- 

 termines a desirable medium. 



5. The shifting of the H ion concentration due to metabo- 

 lism depends both upon the fungus and the medium. 



6. No general statement can be made concerning the rela- 

 tion between the H ion concentrations of the culture media 

 and the growth of wood-destroying fungi as a group. 





