60 LIVERWORTS 



enlarged part or venter of the flask. It is a rounded or oval 

 body. Above the egg cell in the axial row are the neck cells 

 which become converted into mucilage when the egg cell is 

 mature. 



Fertilization. An antherozoid enters the neck of the arche- 

 gonium and swims to and unites with the egg cell. This 

 fused cell is the beginning of the sporophyte or new asexual 

 generation. By repeated division a great number of cells 

 are produced, thus forming the sporophyte. Some of these 

 cells, the spore-mother-cells, form the spores, each producing 

 four. Each spore upon germination may develop into a 

 gametophyte or sexual plant. 



The liverworts or hepaticse have two distinct stages in 

 their life history. (1) The gametophyte or sexual generation, 

 which develops the sexual organs, is the more conspicuous 

 or permanent plant. (2) The sporophyte or asexual genera- 

 tion, which produces the spores, is the temporary plant. In 

 all forms the sporophyte is dependent upon the gametophyte 

 for its food and in all forms the sporophyte dies after produc- 

 ing the spores. This alternating of the sexual and asexual 

 generation is known as the alternation of generations. 



SUMMARY 



Alternation of Generations occurs; the gametophyte or sexual 

 generation alternates with the sporophyte or asexual genera- 

 tion. 



Gametophyte. The gametophyte is the permanent, con- 

 spicuous stage of the hepatics or liverworts. The plant body 

 or thallus has a forked or bifurcating method of branching. 

 Rhizoids or absorbing and fixing organs develop from the 

 under or dorsal side. Air-spaces and air-cells or openings 

 occur on the thallus. The sporophyte of anthoceros has 

 true stomata. The air-cells and stomata permit the exchange 



