54 



OUTLINES OF PLANT LIFE. 



64, Reduction of gametophyte. — In a few of the fern- 

 worts the gametophyte is filamentous, or tuberous, and more 

 or less completely subterranean and colorless ; such derive 

 their food from decaying plant-offal. 



In higher plants of this group the gametophyte becomes 

 still further reduced in size and structurally simplified, until 

 in some species it is hardly more than a few cells surrounding 



Fig. 4g.— Sporophyte of a fern, Polypodium vulgare, showing horizontal underground 

 stem, bearing secondary roots and leaves. Natural size. — From Bessey. 



the sex organs. These reduced forms grow by the use of food 

 stored in the spore from which they originate. Thegameto- 



