248 



[Vol. 10 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



was used, since it was felt that the hanging-drop method was 

 too uncertain and might not give an actual indication of the 

 ability of the fungi to form a mat at any certain hydrogen- 

 ion concentration. Likewise this tube method offered a means 

 for studying those fungi which did not form spores. 



Solutions were made up to P H 3.0 and 2.7 and 5-cc. amounts 

 pipetted into 6-inch test-tubes and autoclaved. Three tubes at 

 each P H were inoculated with each of the following fungi: Nos. 

 5, 6, 7, 11, 14, and 4, the inoculations, with the exception of 



Oospora, being made from agar plates. The tubes were slanted 

 to allow more surface for development and were then incubated 

 at 25° C. The results after incubation of 10 days are given in 



table iv. 



TABLE IV 



GROWTH IN TUBE CULTURES AT P h 3.0 AND 2.7 



No 



Ph3.0 



Ph2.7 



4 

 5 



6 



7 

 11 

 14 



Beginning 

 Beginning 

 Good growth 

 No growth 

 Good growth 

 Beginning 



Beginning, 2 tub 

 No growth 

 Good growth 

 No growth 

 Good growth 

 No growth 



The above procedure was repeated at P H 2.5 and 2.2 and the 

 results are given in table v. 



TABLE V 



GROWTH IN TUBE CULTURES AT P H 2.5 AND 2.2 



No. 



2 



3 



9 

 11 



16 



Ph 2.5 



P H 2.2 



Good mat 



Good mat 



Good mat 



Good mat 



Clouding 



Clouding 



Good mat 



Good mat 



Beginning 



Beginning 



Beginning, 1 tube 



No growth 



The foregoing data would indicate that only 3 of the cultures 

 were capable of growing readily in a medium as acid as lemon 



juice and with an inorganic source of nitrogen. In the case of 



