78 



might be secured lor tie direct evaluation of f (L) and f (5) . 

 At present, however, such indices are not scs.-.=ye^ available, 

 and relative daily rates of evap ration and relative daily 

 sunshine intensity values may be used to represent f(E) and j^fL) . 



Tn correlating the four-week Glimatic and plant graphs 

 it has been found, as in the oase of the two-week graphs, that 

 the behavior f certain cultures aannot be accounted for by 

 the climatic averages for the period. In some of these cases, the 

 fo r-week plant values seem to be determined largely by the 

 conditions during the last half of the cultiire period. This 

 seems especially to be true of those cultures which made a 

 relativ'ly small growth diiring the first two weeks from the 

 seed, as occurred in the case of most of the cultures for 

 Oakland, Ohewsville , and Monrovia. In the following conside- 

 ration of the plant and climatic values for the four-week 

 growth periods, the four week averages will be used in con- 

 nection with the climatic values for the two halves of each 

 four-week period.. These are given in the two week tables 

 and shown graphically on the two-week graphs. For convenience 

 in reference it may be said here that each culture of the longer 

 growth neriods includes 'he shorter period beginning on the 

 same date and the shorter period next following. T'hat is 

 a four weefejperiod beginning July 1 includes the two two-week 

 periods beginning -July 1 and July 16 respectively. 



During the first three four-week growth periods for 

 Oakland the plant and climatic graphs have the relations that 

 would be expected. From the period beginning May 23 to the 

 period beginning June 19 at this station the value of the tem- 

 perature index rises gradually, there is a small decrease in 



