r r»rs, among the several graphs, ir t.v * a , it . ccurs 



with d.if^f : rent maintained temperatures and it represents rates 

 of different magnitudes, ^or example, t Lrst period g**ap v 



for Pvthia.cystis (fig* 2) 8 an optimal temperature r^nge 



about 27.5 C. , vhile the fourth pericd graph r c>r the same f 



c 



gus shows this critical point as about 24 C. Alio in the 



first, case the maximum ordinate value is about £ raa i while 

 in the second case it is about 10.6 torn. 



In general form and shape the growth" temperature graphs 

 of the four fungi for any giver pericd are much alike. 



ginning .vith the lowest temp i re tested the graphs all 



rig* gradually being slightly concave upwards at first but 

 coming decidedly convex upwards as the graph maximum is ap- 

 proached. Beyond this maximum region the graphs descend rapid- 

 ly to the graph minimum (maximum temperature for growth). 

 Just where the reversal of direction of curvature direction oc- 

 curs in this doT'Vf.rd slope is difficult to determire, on ac- 

 dount of the short temperature interval between the optimal 

 point and the temperature maximum. It appears that the curvs - 



ture increases very rapidly as the temperature maximum is ap- 

 proached. But this matter cannot be settled definitely fcr 



all the graphs without much more detailed study. It is clear 

 that the growth optimum always lies far above (to the ripbt 

 of) the middle of the total temperature ranpe, and that the 



upward slope of every graph is much less steep than the down- 

 ward slope. 



In these - • eral characteristics these graphs res*;; - 

 bla those of Kdgertcn ( 1*2/5 ) for the growth of tlomereUa, 



58 



