THE SEED PRODUCTION OF PIN US SYLVESTRIS. 7 



twenty-five branches the annual growth of the previous 

 five years. The mean was as follows: — 



Year 1899, growth 104 mm.; 1900, 102 mm.; 1901, 

 112 mm.; 1902, 115 mm.; 1903, 108 mm.; the average 

 of the five years being 108 mm. 



Since then I have counted 200 branches, taking on 

 each occasion measurement for five years, the details I 

 omit, the mean comes out rather less than 106 mm. 



Returning now to the series of buds and cones, we 

 note that they represent certain definite stages in the 

 growth and development of the organs of reproduction. 



Our brief glance has made it apparent that this 

 growth and development are spread over a considerable 

 period of time, and a careful study shows that from the 

 initiation of the buds to the dispersal of the ripe seeds, 

 nearly three years elapse. This long period is divided 

 naturally into four seasons. The first — June to October — 

 being occupied with the production and growth of the 

 various buds ; the second — March to October — with the 

 development and maturation of the pollen, the organi- 

 sation of the embryo-sac, and the preparation of the 

 nucellus of the ovule for the reception of the pollen, 

 closing with the shedding of the pollen, and the con- 

 sequent pollination of the prepared ovules. The third 

 season — March to October — sees the renewed growth of 

 the male gametophyte, the preparation of the female 

 gamete for the reception of the male gamete, the act of 

 fertilisation, the development of the embryo, and of the 

 seed. The fourth season — Spring — sees the final act, in 

 the opening of the scales of the matured cone, and the 

 dispersal of the ripened seed. 



Before taking our study in some detail, it will be 

 convenient to make a brief examination of the ripe cones. 

 If a dozen or so of ripe, but unopened cones be put 





