THE SEED PRODUCTION OF PINUS SYLVESTRIS. 25 



nuclei of the ventral canal cell and of the egg may fuse, 

 suggesting what has been observed among animals in cases 

 of parthenogenesis. With these statements I am inclined 

 to agree, for I have several examples showing what appears 

 to be the first division of the fertilised egg, and in which 

 no trace whatever can be found of the entrance of a male 

 gamete ; notably, one where two eggs in juxtaposition 

 bear not the slightest evidence of having been fertilised, 

 both, however, appear in the condition of the first division 

 after fertilisation. A remarkable feature in this case is 

 the direction taken by the spindle in each egg, one being 

 arranged parallel with the longer axis of the egg, the 

 other at right angles to it (fig. 11). Chromosomes appear 

 to be absent, at any rate the amount of chromatin present 

 must be exceeding small. It is possible that these are 

 examples of the uniting of the two nuclei, but there can 

 be no proof. 



Resuming : We have brought our history up to about 

 the first of July of the third season. The egg nucleus is 

 fully grown and ready for fertilisation (fig. 12), and the 

 two sperms are at the end of the tube ready to be projected 

 into the cytoplasm of the egg. A normal fertilisation is 

 effected by the apex of the pollen tube, after penetrating 

 the nucellus descending one of the funnel-shaped 

 depressions in the apex of the endosperm ; after crushing 

 through the neck cells the wall of the tube fuses with the 

 wall of the egg, the end of the tube ruptures, and the 

 contents, consisting of the two sperms, the tube nucleus, 

 the stalk nucleus, and the cytoplasm with its included 

 starch, all pass with great rapidity into the egg, one of the 

 sperms passes, probably, without interruption direct to 

 the egg nucleus. The pollen tube does not, however, 

 always take the normal and shortest way to the egg 

 nucleus ; it sometimes passes down outside the endosperm 



