the optimum texnperatura for Phonopsis ap] to rt 



ly constant throughout Lrst five 24-hour periods. 



Aside from the shiftinr of the api ' m and 



optimum *c;i.paratiire values jus*. considered, it should he noted 



that a similar shifting is evident for growth rates lying witl - 

 in a large part of the sub-optimal region of the growth-ts 

 perature graphs for each fungus. Throughout a large pert' 



of this sub-optimal region the ordinate value for any given 

 maintained temperature is greater for every observation period 



after the first than it is for the next preceding period. 

 This statement is true for Pythiacystis for the first five 



24-hour periods after inoculation and for maintained teinpera- 

 ture up to 21 C. I 4 " is true for Phytophthora and Pboincpsis 



for the first five ohservation periods, for maintained I a- 



o ° 



tures up to 23.5 an d 26 C. , respectively. For Diplcdia it 



is true for the first three 24 hour periods and for ajainta 



o 

 ed temperatures up to ahout 21 C. 



In much of the supra optimal region on the other hand, 

 the value of any given ordinate value is usually lass than 

 that for the next preceding period. These shif tings in the 

 specific relations of growth rate to maintained t< jrature 

 v ring it ahout that the growth temperature graph for each suc- 

 cessive ohservation period crosses the next preceding one. 

 The only apparent exception to this statement is for twt of 

 graphs for Phomopsis, for the fourth and fifth ' jut 



iods. . 



Discussion of graphs of figures € and 7 : I pare 



" - curvatures of different graphs it is cc to express 



all the ordinate values of eac" in te and to 



60 



