1919] 



ZELLER, SCHMITZ AND DUGGAR FUNGI ON LIQUID MEDIA 141 



There is a decrease in the amount of growth of Daedalea 

 quercina and Coniophora cerebella when passing from the 

 mono- to the tribasic potassium phosphate in Richards' solu- 

 tion. In Merulius lacrymans, M. pinastri, Trametes Peckii, 

 Pleurotus sapidus, Daedalea confragosa, Polystictus versi- 

 color, P. hirsutus, and Polyporus lucidus there is an increase, 

 while in Lenzites vialis and Lentinus lepideus growth is equal 

 in all cases. 



In general, Dunham's solution and the pine decoction can- 

 not be considered suitable media for these fungi, while maple 

 sap compares favorably with the best solution (Richards' 

 with the tribasic potassium phosphate). 



In all of the fungi studied, except Merulius pinastri, the gen- 

 eral tendency is to increase the active acidity during growth. 

 However, there are exceptions to the general tendencies, indi- 

 cating the fallacy of combining the results obtained from sev- 

 eral fungi to draw sweeping conclusions as to a definite rela- 

 tion between the H ion concentration and growth of wood-de- 

 stroying fungi as a group. Thus, we doubt the advisability 

 of constructing a general curve with the average data derived 

 from a limited number of fungi, as Meacham has done in a 

 recent note. 1 This curve would not apply to many wood-de- 

 stroying fungi, as the data in the table indicate. 



The influence of the growth of the same fungi on the P H 

 value of different solutions is shown by a comparison of the 

 data on Reed's and Richards' solutions. On Reed's solution 

 containing the monobasic potassium phosphate all of the fungi 

 made fair growth and raised slightly the P H value ; on the same 



solution with the dibasic potassium phosphate all of the fungi 

 made slight growth only, and there is a tendency to raise the 

 P H value; while with the tribasic potassium phosphate those 

 that grew exhibited a tendency to raise the P H value. How- 

 ever, on Richards' solution with the monobasic potassium 



phosphate all of the fungi, with the exception of Merulius 

 pinastri, lower even the very low P H value of the solution; and 



1 Meacham, M. R. Note upon the hydrogen ion concentration necessary to 

 inhibit the growth of four wood-destroying fungi. Science N. S. 48: 499-500. 

 f. 1. 1918. 



