Ill] THE BRACKEN FERN 47 



Seed-plants, the same two phases are still found to 

 be represented in the life-story, but their disparity 

 becomes still more marked. Moreover the prothallus 

 in the higher plants no longer leads an independent 

 existence, but is enveloped in the tissues of the 

 sporophyte, upon which it lives as a sort of parasite. 

 As in other parasites the nutritive system, not being 

 necessary, is reduced. This reduction of the gameto- 

 phyte in the highest Flowering Plants attains to a 

 high degree. All that can be held to represent the 

 gametophyte in them is a body consisting of a few 

 rudimentary cells, which produce or minister to 

 the sexual gametes. Without pursuing these com- 

 parisons further, we may sum up the essential points 

 in one sentence and say that, in the higher Flowering- 

 plants the sporophyte is dominant, the gametophyte 

 is evanescent. In them the sporophyte generation is 

 what constitutes the obvious Plant-Life of the land, 

 while the gametophyte is so inconspicuous that to 

 the lay public it is a thing unknown. 



The Fern-plant, though well able to hold its own 

 as a dweller on dry land, is after all an ill-differ- 

 entiated thing. Its primitive character is seen from 

 the fact that the leaf serves various purposes. Most 

 obviously it is an organ of nutrition as well as 

 of propagation. But as we rise in the scale of 

 organisation to the higher Seed-bearing plants 

 these two functions become separated, and localised 



