DEVELOPMENT OF PLANTS 



303 



differing in form) is essentially of the same character as in the 

 Bryophyta, its subterranean character and absence of chlorophyll 

 being due to its association with fungi. It should be stated that 

 lobes are produced from the end of the tuberous gametophyte 

 of one of the species which become green on reaching the sur- 

 face of the soil and in a closely allied order of tropical ferns, 

 the sexual generation is normally a green thallus strikingly like 

 some of the simpler Jungermaniales. 



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. 



{h) The Germination of the Gametospore. — The early develop- 

 ment of the sporophyte resembles Anthoceros in many respects. 



