CLUB MOSSES 



95 



but all other sporophylls and sterile leaves have well devel- 

 oped assimilative tissue. 



The sporangia are large enough to be visible without 

 magnification and when the spores are mature they open by 

 a slit. The spores which are very light are distributed by 



FIG. 54. Selaginella (Sp. cultu.} 



air currents, when they fall to the ground under favorable con- 

 ditions they develop into gametophytes. The gametophyte 

 in a typical lycopodium is a fleshy erect prothallus which 

 bears both antheridia and archegonia. 



The sperms are biciliated and when they fertilize the egg 



