THE SEED PRODUCTION OF PINUS SYLVESTRIS. 15 



few days a change has been taking place in the colour of 

 the cone, the purple-brown giving place to that of green. 



By this time — about the second week of June — the 

 niegaspore mother-cell has grown considerably, and has 

 become of an oval shape with its longest diameter about 

 55 microns, and its shortest diameter about 28 microns. 

 It passes into the spirem stage, the reduction division 

 follows, and thus is initiated the gametophyte. Of the 

 two cells resulting from this division, that toward the 

 apical end of the nucellus immediately begins to break 

 down, the other after further growth again divides, again 

 the cell nearest the apex breaks down ; this process is 

 repeated yet once again, with the result that there are 

 present on or about the 1st of July one functional 

 niegaspore and the remains of three others still undergoing 

 disintegration (fig. 3). 



This rejection of these three cells is remarkably like 

 the rejection of the polar bodies during the maturation of 

 the eggs of the vertebrates ; occasionally, however, two or 

 more niegaspores function, giving rise — of course — to a 

 corresponding number of gametophytes. Hofmeister 

 records the very interesting case of a tree, in a marshy 

 spot in the Botanical Garden at Leipzig, whose ovules 

 mostly contained two embryo-sacs — gametophytes. I 

 have one example with two gametophytes, and one with 

 five gametophytes. In this latter case it is evident that 

 one at least of the four megaspores must have divided 

 once again to produce the five, and that they all persisted. 

 As might be expected, the resulting gametophytes are but 

 very poorly developed. 



The zone of special tissue immediately surrounding 

 the megaspore has increased, there being now about five 

 concentric layers of the loosely aggregated delicate-walled 

 cells, this zone being enclosed by another series of 



