314 GYMNOSPERMS 



In the latitude of Chicago, most pines arc pollinated about the 

 middle of June, and fertilization takes place a little more than a year 

 later, during the last few days of the following June, or the first few 

 days in July. In Pinus strohus, near Wcllesley, Massachusetts, 

 pollination takes place late in May or early in June, and fertiliza- 

 tion a Uttle more than a year later — about the middle of June. 



Hutchinson^" found that in Abies balsamea the interval between 

 pollination and fertilization is only 4 or 5 weeks, and that for the 

 greater part of this time the pollen remains unchanged on the tip 

 of the nucellus. The pollen tube then develops very rapidly, reaching 

 the egg and discharging the sperms in 2 or 3 days. Fertilization 

 occurred June 25 in Ontario, Canada. 



In Pseiidotsuga taxifolia the interval is also very shorty poUination 

 taking place early in April, followed by fertilization early in June. 



In Tsuga canadensis pollination takes place about the middle of 

 May and fertilization about the first of July; so the interval is about 

 six weeks. 



In Picea excelsa the interval is shorter, with pollination in the 

 middle of May and fertilization the middle of June. 



In Cedrus deodara pollination occurs late in September, and 

 fertilization about the end of the following May — an interval of 8 

 months. 



Several observations have been made in the Taxodiaceae: 



Sciadopitys is pollinated late in April (Kew) and fertilization 

 occurs about the end of June of the following year — an interval of 

 about 14 months. 



Sequoia sempervirens is pollinated early in January and fertiliza- 

 tion takes place late in June — an interval of about 6 months. 



Taxodium distickum is pollinated the middle of March and ferti- 

 lized the middle of June — an interval of 3 months. 



In Cryptomeria japonica pollination begins in March, and the 

 pollen grains remain unchanged on the nucellus for 4 or 5 weeks; 

 then the pollen tubes grow rapidly, and in 3 or 4 weeks reach the egg, 

 about the first of June — an interval of about 3 months. 



In Arlhrolaxis sclaginoides pollination takes place early in April, 

 and fertilization about the first of July — also an interval of 3 

 months. 



