DEVELOPMENT OF PLANTS 313 



(a) The Gametophyte of the Lycopodiaceae. — The most in- 

 teresting feature about the club moss ferns is the sexual genera- 

 tion, because it indicates that these ferns may have been derived 

 from the same ancestry as the mosses or at least from a very 

 primitive stock. In certain species the spores produce a rather 

 cylindrical erect gametophyte which terminates in a number of 

 radially-arranged green leaf -like lobes, among which the arche- 

 gonia and antheridia are produced (Fig. 240). This structure 



Fig. 240. Gametophyte of Lycopodium as seen in section: an. antheridia; 

 ar, archegonia. The yonng sporophyte or embryo developed in one of 

 the archegonia consists of a foot, f ; a root, r; and a stem, st, bearing a 

 leaf on either side; s, the snspensor, which lias pushed the sporophyte 

 early in its development into the tissues of the gametophyte. Above a 

 single male gamete is figured. — After Bruchmann. 



has been compared to a miniature leafy moss plant. This sug- 

 gestion of relationship is strengthened by the resemblance of the 

 male gametes to those of the mosses, the sperms, so far as they 

 have been observed, being small, almost straight bodies, and pro- 

 vided with two cilia (Fig. 240). The archegonia may also be 

 more primitive than those of the ferns in possessing several neck 

 canal cells and five instead of four rows of neck cells. The 

 gametophyte appears in all species examined to be associated 

 with symbiotic fungi, as in Ophioglossales, and this has led in 

 many forms to its subterranean and chlorophylless development. 

 (b) The Germination, of the Gametospore. — The germination 

 of the gametospore is characterized by new departures that will 



