MOSSES AND LIVERWORTS. Ill 



take the place of antheridia. A fully formed archegonium 

 is a flask-shaped body with an elongated neck, and an 

 enlarged ventral portion, within which is the oosphere. 



Fertilization takes place by the mingling of the substance 

 of an antherozoid with that of the oosphere, after the 

 antherozoid has forced it way down through the long canal 

 of the neck. The fertilized oosphere, now called the 

 oospore, becomes septate, and by still further cell-division 

 and growth the capsule with its seta, spores, and various 

 parts already described, is formed. 



With suitable material and sufficient time the student 

 can readily verify most of the facts here given. 



Cycle of Development. 



It will be observed that in the mosses alternation of 

 generations takes place. The sporophyte, or non-sexual 

 generation, begins with the formation of the oospore and 

 closes with the spore, while the oophyte, or sexual genera- 

 tion, begins with the germination of the spore, and includes 

 both protonema and leafy plant. 



NOTE. It is important that this should be perfectly clear. The 

 student must see for himself the various stages of development of the 

 mosses as far as this is practicable. He may now consult the various 

 text-books and manuals, particularly those of Goebel, Arthur, Barnes, 

 and Coulter, Bower and Vines, and the references given by them. See 

 further on this subject under Ferns. 



t 



The peat mosses, Sphagnacese, are easily obtained in 

 many parts of the country, and afford an opportunity for 

 extended and profitable comparative study. Their habits, 

 structure of the vegetative organs, and fructification, all 

 present interesting points of difference from the true 

 mosses. 



