232 



BOTANICAL GAZETTE 



[march 



terminal shoot of the season were compared with those of the pre- 

 ceding season as to length (not thickness), and the results tabulated 

 in table M in inches. Only 6 trees were examined, so that we can- 

 not expect the uniformity that more extended observations would 

 offer; still, the results are of value in that they lead to a general 



conclusion. 



TABLE M 



Table of long growth in needles 



Elongation in the needles had not ceased on July 4; in no case 

 was it three-fourths completed, as a reference to the table will 

 show. Assuming that elongation in the needle is contemporaneous 

 with elongation in the shoots,'' that is, that it began on April 26, 

 it follows that during a period of 69 days the needles had attained 

 on an average 63 per cent of the average growth of the preceding 

 season. Assuming again that the rate of elongation was the same 

 during the rest of the season, we may compute roughly the period 

 necessary for the needles to complete their growth, that is, growth 

 in length in the needles would be completed about 40 days after 

 July 4, that is on August 13. It is reasonable to assume from the 

 data on the 6 trees that the elongation of white pine needles ceases 

 somewhere about the middle of August. 



If we correlate the results given above with those which have 

 been previously given, we arrive at the following interesting 

 conclusions for white pine in the vicinity of Ithaca. Growth in 

 thickness (secondary thickening) begins in white pine before the 

 elongation of aerial parts, either of shoots or needles. Elongation 

 of shoots and needles begins simultaneously. The elongation of 



'5 Field observation substantiated this assertion. 



