

ly Lehenbauer ^ 8 ' found that tne optimum temperature for 

 elongation of ^aize seedlings in his experiment was 30° C 

 when the exposure period was 6 hours, while the correspond- 

 ing optinum temperature for an exposure period of 12 hours 

 was 32° C. If Lehehbauer' s twelve hour period of exposure 

 he divided into four periods of three hours each, and the 

 optinum temperature calculated from his data for each of 

 these four successive periods separately, they are found to 

 be 30, 31, 31 and 32° C respectively. Obviously, any 

 physiological process must be regarded as controlled by all 

 the effective conditions acting together. Nov. the condi- 

 tions that influence the rate of growth of a fungus in a 

 culture may be roughly classified into five groups as fol- 

 lows : 



(l) The nature of t h e fungus , which implies its 

 internal conditions, everything that goes to make it that 

 particular organism which it is. This set of internal con- 

 ditions is vaguely and partially indicated by the name of 

 the fungus, with an implied morphological description of 

 its form and development, to which the name refers. Eut 

 it is well known that the 3ame species of fungus may develop 

 quite different complexes of internal characteristics under 

 different sets of environmental conditions. For this reason 

 it is commonly stated that a knowledge of the recent history 

 of the organism is necessary, as well as information regard- 

 ing its taxonomic 3tatus. The mere morphological description 



(3) Lehehbauer, P. A. , Growth of maize seedlings in re. 



tion to temperature. Physiol. Res. 1 : 247-2S8, 1914. 



