LIVERWORTS 339 



491. The capsule (sporogonium). As a result of fertiliza- 

 tion the egg does not develop the marchantia plant again, but 

 develops into a new structure very different from the thallus 

 which bears the sexual organs. This is the capsule* (spore 

 producer = sporogonium) , which is peculiar to all the liverworts 



Fig. 299. 

 Marchantia polymorpha, female plants bearing archegoniophores. 



and mosses as well. In Marchantia, as in most liverworts and 

 mosses, it is a stalked capsule. The capsule contains the spores, 

 and in Marchantia and many other liverworts the spores are 

 mixed with sterile cells in the form of long, slender, spirally 

 marked cells called elaters. These elaters are very sensitive to 

 changes in the humidity of the air, twisting and coiling in various 

 ways with slight changes in the humidity. This assists in push- 

 ing the spores out of the capsule after it opens at the apex. Since 



* With its stalk when present. 



