[Vor. 11 
56 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
secondary maximum is shown at Рн 3.8 with 138 mgs. This is 
followed by a marked decrease between P, 4.0 and 5.5, rising 
again to the maximum point, Рн 6.0 with 153 mgs. Тһе Pg 
limits at 35? C. eorrespond rather closely to those at 15° C. 
Here, too, there is a secondary maximum at Рн 4.2, and a maxi- | 
mum at Рн 6.4 with 141 mgs. As in the Richards’ solution, the 
optimum hydrogen-ion concentration lies between Pg 5.5 and 
7.0. 
In all cases growth tends to increase the active acidity of the 
nutrient solutions (table IV). This is more marked in the peptone 
$ 
= 
-50 5 = = ` 
_ 2 = m t 
A t 
же. 
i ==: 15? ) 
f = i 
-25 / Pu nic 85° 
! е E 
F v : 55° \ 
= ! гө = \ 
5 M \ 
eh = \ 
| і Е 4 
w 4 5 к=. 
Fig.3. Daedalea confragosa in Richards’ solution. 
solution where the final Pg range from 3.3 to 4.5 with а mean! | 
of 3.5 at 15° C., 3.0 to 4.0 with a mean of 3.3 at 25? C., and 3.2 
to 3.8 with а mean of 3.5 at 35° C. In the Richards’ solution | 
the final values range from Рн 3.7 to 6.4 with a mean of 4.6 at : 
15° C., 3.7 to 4.9 with a mean of 4.2 at 25? C., and 3.5 to 44 © 
with а mean of 3.9 at 35? C. 2 
The peptone medium supports growth through а slightly | 
wider acid range than does the Richards’ solution. However, , 
c The mean is obtained from’ the final Ри in those solutions supporting mycelia !- 
