BIRTH OF ALG& AND FERNS 



composition does exist corresponding to their sexual 

 distinctions. 



The mode of reproduction of the higher fungi has 

 already been described. That of many Cryptogama, 

 the mosses, ferns and others are both sexual, and asex- 

 ual, and often show a curious condition of alternate 

 generation. The female cells or oospores germinate, 

 and produce an embryo plant, which in the Ferns is 

 a simple mass of cellular tissue. Its cells divide, a 

 root is formed that descends, and a stem that ascends 

 and bears leaves. On the under side of these, spores 

 are formed ; when ripe they escape, and, taking root, 

 a new plant grows. After a time the sexual gene- 

 ration occurs, consisting in the production on the 

 under part of the leaf of spores that develop into 

 the antheridia and others into the archegonia, corre- 

 sponding to the male and female fertilizing organs of 

 the anthers and pistils of the plant-bearing flowers, 

 or the phanerogama. These give birth to the oospores 

 before mentioned, and the cycle begins again. 

 17 257 



