iQisl 



BROWN— PINUS STROBUS 



231 



Elongation of aerial parts began in the young growth in question 

 before May 3 and continued until about July 4. Assuming that 

 growth before May 3 proceeded at the same rate as between May 3 

 and May 30 (i . 2 per cent a day), we can only infer that the awaken- 

 ing of growth in length in the shoots began about 8 days before 

 (April 25), a conclusion that field observation fully confirmed. 

 Cessation of growth in length in shoots had occurred by July 4, 

 without doubt because at this date the length of the season's 

 growth had surpassed that of the preceding year, and furthermore 

 the terminal cluster of buds was fully formed. It follows from the 

 data that in 50 young trees in 1913 elongation of the terminal shoots 



TABLE L 



Growth in length in the terminal leader 



began in the last part of April and continued until July 4. What 

 applies to the terminal shoot is even more apphcable to the lateral 

 branches where long growth is not as vigorous. Furthermore, 

 the same relation exists between young and old trees. In the latter 

 growth in length must have been completed by July 4, so that it 

 may be concluded that in white pines in the vicinity of Ithaca, 

 growth ceases during the early part of July."" 



Before proceeding to a review of the results of others, perhaps 

 a brief discussion of the elongation of the leaf is appropriate here. 

 Only one observation was made in regard to this point, but for- 

 tunately the date was July 4, so that it offers a chance for com- 

 parison between growth of shoots and leaves. The leaves on the 



"Meissner (22) has noted the formation of the so-called "Johannistriebe" in 

 rare cases in white pine. Bud formation occurs in the normal way, but in such cases 

 some buds continue growth the same year. This peculiarity has been noted in many 

 dicotyledonous fruit trees, but is rare in conifers. 



