[Vor. 11 
60 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
the optimum Pg varies with the temperature, it lies in a more 
acid range than in the Richards’ solution. In the first medium 
the fungus decreases the active acidity elose to the neutral point, 
while in the second, it slightly increases throughout the entire 
growth-range. 
Armillaria mellea in the Richards’ solution grows only in cul- 
tures in which the reaction is acid, as shown in table v1, fig. 5. 
Growth at 25? C. and 35? C. is more pronounced than at 15° C. 
and, of these two, 25? C. is the more favorable. At this tempera- 
ture growth is inhibited by Ру 2.9 and 6.9, a wider limit on the 
acid side and a narrower limit on the alkaline side than at 15* 
C., where growth is inhibited by P, 3.4 and 7.4. Тһе curve at 
35° C. resembles that at 25? C. but the amount of growth is less 
and the Ру limits are narrower, being 3.4 and 6.9. Тһе optimum 
in this high temperature is at Рн 6.0 with а mat weighing 63 mgs., 
TABLE VI 
THE GROWTH OF ARMILLARIA MELLEA AND THE on GES IN THE ACTIVE 
ACIDITY UPON BOTH THE RICHARDS’ AND PEPTONE SOLU- 
TIONS AT DIFFERENT INITIAL Pa AND TEMPERATURES Ы 
15°C 25° C. 85° C. 
Ри Wt. of Ри Wt. of Ри Wt. of 
mat in = mat in mat ш 
Initial | Final Initial | Final | mgs Initial | Final 4 
2.9 2.9 0 
L4 3.4 0 3.5 3.3 34 3.4 3.4 0 
239 3.8 34 3.8 3.6 38 3.9 27 32 
a| 43 3.5 56 4.5 3.9 59 4.5 3.8 35 
| 5.0 4.5 31 4.9 4.4 74 4.9 4.3 59 
51 5.5 5.2 30 5.5 5.1 63 5.5 4.9 54 
| 6.0 5.6 31 6.0 5.7 68 6.0 5.4 63 
5 as 6.3 23 а 62 52 6.5 64 м 
: : : 9 : 6. 
7.4 7.4 0 5 T 
2.0 2.0 0 
2.5 2.5 0 2.5 2.5 19 2.5 2.4 0 
2.8 2.5 70 2.8 2.9 120 3.0 3.3 65 
4| 3.4 | 57 178 3.4 4.0 262 3.6 3.6 | 139 
2| 40 | 5.7 149 3.8 4.0 301 3.9 4.2 | 293 
o| 4.5 6.5 105 £0 1 $7 289 4.6 4.2 | 255 
8 5.0 6.7 116 4.9 4.8 257 5.0 4.9 | 271 
& 55 | 68 120 5.3 | 48 252 5.4 | 5.5 | 224 
$| 60 | 6.8 115 6.0 4.8 253 6.0 4.6 | 201 
ы е F 6.7 125 6.5 5.0 214 6.4 4.8 | 281 
TUI TE 132 15 d. 112 7.0 5.8 | 187 — 
; : 79 
7.5 7.5 0 7.8 7.8 0 7.4 7.4 0 
