THE SEED PRODUCTION OF PIN US SYLVESTRIS. 5 



The number of sound seeds enclosed in a fully 

 developed cone of Pin us sylvestris but meagrely represents 

 the enormous reproductive possibilities with which it was 

 originally endowed. The young cone contained the 

 potencies of some 1,500 pro-embryos, the mature cone 

 yields only some 10 to 20 seeds. With so prodigal a 

 provision for seed production this poor result seems out 

 of all proportion, and we naturally ask : To what adverse 

 influences then, are the possibilities contained in the young 

 cone subjected, whereby such untimely disaster is brought 

 about ? To give a sufficient reply we must possess a 

 knowledge of the reproductive organisation in all its 

 details, we must know the minute structure and the 

 functions of the various parts engaged in this wonderful 

 process, we must know the history of their development, 

 and the environment of the parts concerned during that 

 development, and we must, further, be acquainted with 

 the history of their relation to the outer world. 



If a tree of Pinus sylvestris be examined during the 

 winter it may readily be noticed that its branches bear 

 buds, small cones, large unopened cones, and probably 

 some old cones the scales of which are wide open. A 

 closer examination will reveal the fact that the buds are 

 of three kinds, namely, vegetative, microsporangiate, and 

 megasporangiate ; these may readily be distinguished the 

 one from the other ; the vegetative bud is relatively long 

 and of small diameter at the base, tapering thence to a 

 point ; the microsporangiate is relatively shorter, thicker 

 at the base, and its tapered form is rounded in outline; 

 the megasporangiate bud is not tapered, its upper 

 portion is more or less swollen, the amount depending 

 upon the number of strobili it encloses, one, two, three, or 

 occasionally four. Immediate^ behind some of these 

 apical buds will be found one or more small cones — female 



