

[Voi,. 10 



246 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Spores were placed in hanging drops in Van Tieghem cells, usi ng 

 1, 5, and 10 per cent citric acid and checks of distilled water. 

 In 48 hours the distilled water controls of the Penicillium sp. had 

 germinated, while the P. stoloniferum spores had germinated 

 strongly and showed growth and branching in the 1 per cent 

 citric acid and only slight germination in the distilled water. 

 In the 5 and 10 per cent citric acid none of the spores of either 

 fungus germinated. Previous experience had indicated that these 

 2 fungi were probably the only ones which would germinate in 

 free citric acid. 



For further study 2 solutions were made up as follows: 



Solution I. 



M/l KNO, 100 cc. 



M/4 KII,P0 4 100 cc. 



M/10 MgSO* 50 cc. 



Citric acid 141 gms 



Dextrose 20 gms 



M /1000 FePO, 8 cc. 



HaO (distilled) to make 1 liter. 



Solution II. 



KOH, 112.5 gms. per liter. 



Solution I was approximately 2 N acid, and Solution II w 

 2 N alkali and consequently suitable for adjusting the reacti 

 of Solution I. A titration curve was constructed by placing 5 ( 

 of Solution I in each of several test-tubes and adding varyi: 

 amounts of Solution II and enough distilled water to make 



volume of 



and determining: the Ph of the 



this procedure Solution I, which furnished all 

 diluted one-half. The results of this procedure 



Alkali 

 added (cc.) 



0.00.40 5 



P 





1.7j2.2|2.4 



0.6 



0.7:0. 80. 91. 01.1 1.2 



2.5 



1.41.52.02.5 



2.6J2.7i2.8|2.93.03.1i3.2]3.3 



3.84.1 



Autoclaving these s< «lutions failed to change the P H appreciably. 

 Proceeding with these data, solutions of varying P H were made 



up 



for use in germination and growth tests. 

 ?he germination of the spores of some of the fungi was tried 

 by means of the hanging-drop method, following the general 



