THE SEED PRODUCTION OF PIN US SYLVESTRIS. 13 



second week in April/ the ovuliferous scales and their 

 bracts are well defined. Abont the first week of May, the 

 first indications of the ovules appear, the liucelli and 

 micropyles being now readily distinguished. 



About three weeks later — end of May — a cell some- 

 what larger than its fellows will be observed near the base 

 of the nucellus, this is the megaspore mother-cell. In 

 the course of a few clays it is surrounded by two or three 

 concentric layers of cells differing considerably from the 

 other cells of the nucellus, the outer layer being in course 

 of disintegration. 



During the initiation of the megaspore mother-cell 

 other changes are taking place : the apex of the nucellus 

 breaks down, and thus there is formed a somewhat cup- 

 shaped depression, well adapted for the reception of the 

 pollen, it forms in fact the equivalent of the stigmatic 

 surface of the Angiosperms. The superficial cells of this 

 depression appear to act as secretionary glands, and to 

 pour forth a slightly viscid fluid, this latter mingling 

 with the discharged contents of the disintegrated cells, 

 flows into, and fills to overflowing the cavity of the open 

 micropyle immediately below. 



The young cone, which is of a purple-brown-red 

 colour, is now fully prepared for the reception of the 

 pollen ; it stands almost erect, its opened scales give 

 entrance to a cavitv somewhat larger at the base than at 

 the mouth, and in which the inverted ovules are situated, 

 easy access is thus given to the pollen, and should any 

 grains find their way between the scales they readily fall 

 to the bottom. Here they become entangled in the viscid 

 fluid, which gradually disappearing, either by evapora- 

 tion, or by absorption into the nucellus, results in the 

 grains being drawn into the micropyle and deposited upon 

 the cup of the nucellus. 



