286 PRACTICAL BOTANY 



sporangium. The archesporium meanwhile divides to form numer- 

 ous spore-mother-cells, each of which divides tetrahedrally, and 

 gives rise to four spores. 



Though in recent years great additions have been 

 made to the knowledge of the prothallus in various 

 species of Lycopodium, still the conditions favourable for 

 the germination of the spores are not sufficiently well 

 known to make it probable that the attempt to grow 

 the pro thai li would be successful : accordingly reference 

 should be made to the text-books, and to special memoirs 

 for further information as to the characters of the 

 prothallus. 



