74 



of sxinshine intensity, however, when the other plant graphs 

 do not parallel height as they do approximately in the present 

 instance. For Chewsville, the graph of temperature values 

 and the height graph have the same general form if we neg- 

 lect the period beginning Tune 16, but here again he plant 

 graphs all shov/ ordinate values so nearly the same th it no con- 

 clusion c-n be drawn as to whether the hei|ht of the plants 3s 

 affected by the climate in the manner noted above. The Monrovia 

 graphs, however, support the assumption made as to the way in 

 which light and temperature values are related to stem growth. 

 It will be observed that at this station the general form of 

 the height graph resembles the general form of the graph of 

 temperature indices. Prom the period beginning May 18 to the 

 period beginning July 27, the graph of stem height slopes in 

 a direction opposite to the graph of light intensity. The 

 height in these o\iltures is apparently responding to the cli- 

 matic comolex more or le.is independently of the other plant 

 measurements as will be seen from a comparison of the three 

 plant graohs. The graph of stem height for College has the 

 same p-eneral form as the graph of temperature values and is 

 well below it for all the periods except the last. For 

 Baltimore the graph of stem height would indicate again tha""- 

 this plant growth rate is responding somewhat independently 

 of the other two. The graph has the same general fotrm as the 

 graph of temperature indices and shows an opposite slope di- 

 rection to that of the light graph during the entire season 

 except between the periods beginning June 10 and June o5. and 

 between *-he periods beginning Sept. 19 and Oct. 1. The plant 

 graphs for Darlington all reach abnormally high values. The 



