LETTER XXIV. 



THE MOSS TRIBE — THE JUNGERMANNIA TRIBE. 

 Plate XXIV. 



Still lower in the scale of creation, than Ferns and 

 Club-mosses are the true Mosses; plants destitute of 

 all traces of vessels and of breathing pores ; with no 

 true veins in their leaves, and so pigmy in growth, 

 that the most gigantic of them hardly equal the smal- 

 lest of the Club-mosses. 



Up to the present moment, a microscope has rarely 

 been necessary in our studies ; whenever I have re- 

 commended you to employ it, the subject would 

 usually have admitted of your dispensing with its 

 aid, if you had pleased. But from this time forward 

 it must be constantly in your hand, and every obser- 

 vation must be made with it. You will, however, 

 find abundance of most curious and interesting re- 

 sults, to idemnify you for the trouble it will give 

 you. 



Mosses are among the smallest of plants with true 

 leaves ; they are often so minute that the whole spe- 

 cimen, leaves, stem, fruit, and all, would escape the 

 eye, if they did not grow in patches ; and they never, 

 in the largest kinds, exceed the height of a few 

 inches. Nevertheless, they are organized in a man- 



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