62 



PLAN T LIFE. 



food stored in the spore from which they originate. The 

 gametophyte of such species has lost wholly its vegetative 

 character, and is restricted in function to the production of 

 the sexual organs. 



71. The sporophyte. — In contrast with the smallness and 

 simplicity of the gametophyte is the relatively large size and 



Fig. 76.— Embryo of Pteris aguilina, and a small part of the gametophyte, g y in 

 which its foot,/, is embedded, r, the primary root ; s. primary stem ; /, primary 

 leaf. Induced growth of the gametophyte about the foot is shown by small size and 

 numbei of cells. Much magnified. — After Hofmeister. 





Fig. 77 — Section through embryo and gametophyte of maidenhaii fern (AdiantutH 

 Capillus-Veneris). The embryo is older than that in tig. 76. /,/, gametophyte; 

 A, rhizoids, among which are two spermaries. The eggs in three ovaries failed to 

 develop ; the other formed the embryo, E. a, primary stem, only slightly de- 

 veloped (compare s, fig. 76) ; b, primary leaf ; iu, primary mot. The part embedded 

 in the fjametophyte is the foot. Magnified about 10 diam. After Sachs. 



complexity of the sporophyte (fig. 75). It is always differ- 

 entiated into stem and leaves, and, with rare exceptions, 

 roots also. This great advance in the development of the 

 sporophyte of the fernworts, as contrasted with its form in 

 their nearest of kin below, the liverworts and mosses, suggests 

 that the fernworts are a very old group ; a hint which is con- 

 firmed by the antiquity of their fossil remains. It is also 

 noteworthy that, as compared with mossworts, the chief work 



