DEVELOPMENT OF PLANTS 



317 



tion is not often met with, owing to the fact that, like the sporo- 

 phyte, its development is associated with mycorrhizal fungi and 

 consequently it is usually completely buried in the soil and usually 

 quite devoid of chlorophyll. The various stages in the germina- 

 tion of the spores have never been observed, but the mature gam- 

 etophyte of Botrychium was found a few years ago by Jeffrey 



^^•./''^^ 

 - $ e ^f 



Fig. 218. The gametophyte and young sporophyte of Botrychium: A, 

 tuberous appearance of the gametophyte — e, a young sporophyte or em- 

 bryo developing in one of the archegonia. B, a section of gametophyte — 

 ar, archegonia; an, antheridia. C, two antheridia in section. D, male 

 gamete. E, archegonium before dissolution of canal cells. F, gametospore 

 in two-cell stage of germination. G, young sporophyte with roots and first 

 leaf developed but still attached by foot to the round gametophyte, gm. 

 A. F.— After Jeffrey. 



and carefully studied. It appeared as a rather tuberous body 

 that is provided with numerous rhizoids and a growing apical 

 cell as in the Bryophyta (Fig. 218, A, B). The archegonia and 

 antheridia are usually borne upon the upper surface of the game- 



