7;^ 



'Correlation between nlant and nlimatic data. 



Ill ^ — 



Relation of ptem heij^ht to sunshine ani temperi:!.ture . No 

 very definite correlation bet-een the stem height and climatic 

 conditions has been found. After the plants have been grown 

 four weeks, ho^'-ever, the graph representing the rate of growth 

 in height bears a general resemblance to the graph of physiologi- 

 cal tempr^rature indices. In the first periods of the growing 

 season, also, ■*:he data indicates that the s-^em height is in- 

 versely proportional to the sunshine intensity, this relation 

 being indicated by the fact that the graphs of these two quan- 

 tities slope in opposite directiO' s in many oases. The effect 

 of the light is, however, only secondary and does not disturb 

 the relation apparently exinsting between stem height and 

 temperature to any considerable degree. These two relations 

 will be brought out by an examination given below of the graphs 

 for the individual station. 



For Oakland, the stem height graph and the graph of tem- 

 perature values show the same -^eneral form, and the stem heirht 

 and sunshine graphs are opposite in the direction of their 

 slope from the nerlod beginning May 23 to the period beginning 

 July 31. Fot this station, tae other plant graphs parallel 

 the height graph approximately and thus no conclusion could 

 be drawn from the data for Oakland as to whether the difference 

 in slope direction of light and stem height is accidental or 

 due to a real effect of sunshine intensity on the rate of e3)on- 

 gation of the plants. A t some of the other stations the 

 height graph shov;s an opposite iirection of slope to the graph 



