THE COMMOX MOSSES 



293 



293. Common mosses.* 

 The common mosses (or- 

 der Bryales) are familiar 

 because of the occurrence 

 of numerous species with 

 conspicuous upright stems, 

 which develop the long- 

 stalked sporophytes with 

 characteristic terminal 

 spore cases (Figs. 261,265). 

 It is a very large group, 

 containing over eight thou- 

 sand species, and is by far 

 the most numerous assem- 

 blage in the bryophytes. 

 These mosses grow 

 in the greatest va- 



rietv of situations, 



<j 



-in swamps and 

 bogs, in the water 

 of streams, in moist 

 and shaded woods, 

 in open fields, and 

 on relatively dry 

 hillsides and rocks. 

 They perform an 

 important service 

 to plant life ill 

 holding back much 

 of the rainfall, 

 a 1 1 o w i n g it to 

 sink into the earth 



FIG. 261. A common moss (Catharmea undulata) 



Showing the branching leafy moss plants (gameto- 

 phytes) attached to the root-like mass of protonemal 

 filaments and bearing sporophytes. After Sachs 



* To THE INSTRUCTOR : In a short course it is best to present the life his- 

 tory of bryophytes through a somewhat detailed study of one of the common 

 mosses, followed by general studies of a variety of forms of mosses and liver- 

 worts. 



