[Vor. 11 
70 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
6.5 with maximum growth of 61 mgs. at Py 5.5. That 25? C. is 
more favorable for growth of this fungus than 15? C. is indicated 
both by the widened range of Рн and by the heavier mats. Here 
growth is not inhibited until Ру 3.0 is reached on the acid side and 
until 7.2 is reached on the alkaline side, while best growth is 
> M 
B 
с 
5 
"250 = 
- ^ 
= = I 
£i \ 
5 n 
2 ! ` 
-200 4 . Pr. 
o , = 
c pP . 
21 
р і 
! 
! 
-150 ! 
rj 
! 
E t 
' 
t 
—100 Г 
1 
П 
= i 4 
! = 
, Ж 
-50 - і ена 
єс 
= bo 
te 
Ж. 
4” 
T T T T f 
$ Рн 4 5 6 7 8 
Fig. 12. Pleurotus ostreatus in peptone-nutrient solution. 
obtained at Pa 5.5 with 80 mgs. Growth of this species is less 
tolerant to an acid medium at 25? C. than it is at 35? C., but in 
an alkaline medium, on the other hand, the fungus grows better 
at the lower of the 2 temperatures. For the 3 temperatures, 88 
TES by the growth curves, the optimum Ру range is 5.0- 
In the peptone solution (fig. 12), using the amount of growth 
as an indicator, it is difficult to pick out any optimum temperature, 
