THE GYMNOSPERAIAE : COXIFERALES AND TAXALES 701 



The Male Gametophyte 



Development of the male gametophyte usually begins at pollination, that 

 is, about the middle of ]\Iarch. The sequence of events is not quite certain 

 but appears to begin with the division of the pollen grain into an antheridial 

 cell and a tube cell. The antheridial cell then divides into a stalk cell and a 

 body cell. The latter divides into two unequal male cells. All four nuclei 

 pass into the archegonium, where the larger of the two male nuclei unites 

 with the oosphere nucleus and the other three abort. 



The Ovule 



The ovules appear at the same time and in the same axillary position as 

 the male cones, but upon different trees (Fig. 704). As in the male there 



Fig. 704. — Taxiis baccata. Shoot bearing ovoiles 

 surrounded by cupules. 



is a short axis, called the primary axis, which bears a closely imbricated 

 succession of sterile scales on its lower portion. From the axil of the upper- 

 most of these involucral scales arises the fertile shoot, called the secondary 

 axis. This bears three, crossed pairs of minute scales, the lowest pair standing 

 transversely to the subtending bract. The ovule is apparently terminal on 



