



490 BOTANICAL GAZETTE [june 



a continuous decline in the moss flora until the climax beech-maple 

 forest is reached. Competition with other plants seems to be the 

 determining factor as the successions advance beyond the semi- 

 hydrophytic. 



Conclusions 



i. 



mosses are most 



in number of SDecies and m total auantitv in the staere: in 



become very 



ma 



climax 



swamp and bog successions the greatest dominance 



of mosses is found usually m the swamp or bog forest association, 

 which may or may not directly precede the climax. 



3. The mosses found in running spring water and in stagnant 

 water are of different species, but nearly all belong to the same 

 family, the Hypnaceae. 



4. The succession on floodplains is unimportant because of 

 constant deposit of sediment over the germinating mosses. 



5. Mosses are among the highly important pioneer plants on 

 bare rock surfaces, and continue abundant far into the forest 

 association. 



6. From an economic standpoint mosses are of the greatest 

 value in several respects. They are soil formers and provide 

 favorable habitats for germination of higher plants. They assist 

 largely in forming the surface mat over deep lakes and in filling 

 up shallow bodies of water. They may take part in building 



rocklike 



make 



islands on which higher plants may grow. They conserve moisture, 

 and give it up slowly, thus aiding in the prevention of disastrous 

 floods in the surrounding regions. They prevent erosion of clay 

 or sand surfaces. 



