cms. 
112 Brown.—Experiments on the Growth of 
ordinary temperatures without showing any signs of marginal staling. 
Staling effects, however, do appear at 25 0 , and especially at 30°, but it will 
be noted that both these are supra-optimal temperatures. Whether these 
effects were due to actual staling substances appearing in the medium, or to 
direct injury to the fungal hyphae from prolonged exposure to the high 
temperature, was not investigated. 1 
Fig. 2 gives the corresponding results for Alternaria grossnlariae. 
The curve for growth at 30° is not drawn in, as it is practically identical 
with that at 25 0 . This fungus shows somewhat different growth features 
from those of Botrytis. It will be noticed that we have here a more slowly 
growing fungus with higher cardinal points for temperature. A striking 
4 
' 2 3 4 j 6 7 
T/m& {days) 
Fig. 1. Botrytis cinerea on potato agar. 
is 
hO- 
OS 
>2S 
•20 a 
•IS 0 
-«-» ■ ' S - 8 — 
3 4 S 6 
Time (days.) 
7 8 3 
Fig. 2. Alternaria grossnlariae on potato agar. 
difference also is the shortening of the initial period of accelerated growth, 
so that all the cultures have reached their limiting growth-rate by about 
the second day. From that time onwards, all the curves are roughly 
parallel to the time-axis, so that the growth-rate in each case on the eighth 
day is not sensibly different from that on the second. There is no indica- > 
tion of staling in any case. 
Both the preceding fungi may be cited as illustrations of the non¬ 
staling type, i.e. putting aside the case of the 30° curve for Botrytis cinerea 
which brings in considerations of supra-optimal temperature and is outside 
the scope of the present paper. 
Fig. 3 illustrates the staling type of growth, with other features 
similar to those described in Fig. 1 and which need not be repeated here. 
The essential point to notice is that, in contrast with the first two cases, 
there is distinct staling of the fungal colonies at all the temperatures. In 
1 Compare, on this point, Balls, Ann. Bot., 1908, xxii. 557. 
