DEVELOPMENT OF PLANTS 



345 



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 archegonia and 

 antheridia are produced (Fig. 240). This structure has been 

 compared to a miniature leafy moss plant. This suggestion 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 provided 

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

 primitive than those of the ferns in possessing several neck canal 



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

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

 archegonia consists of a foot, /; a root, r; and a stem, st, bearing a leaf on 

 either side; s, the suspensor, which has pushed the sporophyte early in its 

 development into the tissues of the gametophyte. Above a single male 

 gamete is figured. After Bruchmann. 



cells and five instead of four rows of neck cells. The gameto- 

 phyte appears in all species examined to be associated with 

 symbiotic fungi, as in Ophioglossales. The spores will not de- 

 velop unless they come in contact with a suitable fungus and this 

 has led in many forms to a subterranean and chlorophylless 

 development of the gametophyte. 



(&) The Germination of the Gametospore. The germination of 

 the gametospore is characterized by new departures that will 

 continue on through the seed plants. The gametospore enlarges 

 and divides into two cells by a transverse wall. The outer of 



