CHAPTER XXV. 



MOSSES (MUSCI). 

 (Polytricbum, or mnium.) 



243. The moss plant. — We are now ready to take up the 

 more careful study of the moss plant. There are a great many 

 kinds of mosses, and they differ greatly from each other in the 

 finer details of structure. Yet there are certain general re- 

 semblances which make it convenient to take for study almost 

 any one of the common species in a neighborhood, which forms 

 abundant fruit. Some, however, are more suited to a first 

 study than others. 



Those mosses in which there is a marked difference between 

 the male* and female plants, like polytrichum, bryum, mnium, 

 etc., are most suitable for the purpose. The male plants of 

 these genera have the leaves at the end of the stem in a broad 

 rosette. Both male and female plants should be collected, and 

 the fruiting plants also. The latter bear above the leafy portion 

 a stalked capsule. Polytrichum (known as pigeon wheat moss) 

 is suggested here for the practical study, while mnium is here 

 used to illustrate the mosses. It will be found useful occa- 

 sionally to study a plant that is different from the one fully 

 illustrated in the book, since it givas the student an opportunity 

 for more independent work. 



The Pigeon Wheat Moss (Polytrichum). 

 Exercise 50. 



244. The fruiting plant. — Take entire plants, those with leafy stems 

 bearing the stalked capsule. Sketch the entire plant. Note the stem (axis) 

 and the three rows of leaves. Search for the rhizoids at the lower end of 

 the stem. What is their color ? Observe the capsule, its form. 



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