BRYOPHTTA. 



99 



chlorophyll. They finally become entirely separated and each one gives 

 rise to four spores which closely resemble those of the liverworts but are 

 smaller. 



Near the base of the capsule, on the outside, are formed breathing 

 pores (Fig. 58, F) quite similar to those of the higher plants. 



If the spores are kept in water for a few days they will germinate, 

 bursting the outer brown coat, and the contents protruding through the 

 opening surrounded by the colorless inner spore membrane. The pro- 

 tuberance grows rapidly in length and soon becomes separated from the 

 body of the spore by a wall, and lengthening, more and more, gives rise 

 to a green filament like those we found attached to the base of the full- 

 grown plant, and like those giving rise to buds that develop into leafy 

 plants. 



CLASSIFICATION OF THE MOSSES. 



The mosses may be divided into four orders : I. The peat 

 mosses (Sphagnacece)-, II. Andreceacece ; III. Phascacece; IV. 

 The common mosses (Bryacece). 



C 



FIG. 64. A, a peat moss (Sphagnum), x l / 2 . B, a sporogonium of the same, 

 x 3. C, a portion of a leaf, x 150. The narrow, chlorophyll-bearing cells 

 form meshes, enclosing the large, colorless empty cells, whose walls are 

 marked with thickened bars, and contain round openings (o). 



The peat mosses (Fig. 64) are large pale-green mosses, grow- 

 ing often in enormous masses, forming the foundation of peat- 

 bogs. They are of a peculiar spongy texture, very light when 

 dry, and capable of absorbing a great amount of water. They 

 branch freely (Fig. 64, A), the branches being closely crowded 



