MOSSES 97 



account of the peculiarly open formation of the 

 leaf, which is due to the latter cells, that these 

 plants are ahle to absorh and to hold a large 

 amount of water, and it is to this fact that they 

 owe their well-known spongy nature. In not 

 a few mosses the form of the cell varies in 

 a very marked manner in different parts of the 

 leaf ; this is well shown in figs. 42 and 43. Fig. 42 

 gives the cells at the base of the leaf of the Pro- 

 longed Eeather-moss (Eurhynchium prcelongum), 

 which are much enlarged as compared with those 

 of fig. 43, which belong to the upper portion of 

 the leaf. In all these features of leaf-form and 

 cell-structure features of such minuteness as to 

 be inappreciable by the naked eye we cannot but 

 be struck again with Nature's all-pervading order; 

 for, so constant are most of these characteristics 

 that the presence or absence of any one or more of 

 them will frequently suffice to settle the name 

 of some doubtful specimen. 



Uses of Mosses. We are so accustomed to 

 find that the various members of the vegetable 

 kingdom serve a useful purpose of some kind, 

 either directly or indirectly, and either to man 

 or to the other animals, that the question not 

 unnaturally suggests itself, " Of what use are 

 mosses ? " And to this we are obliged to reply 

 that, to man at all events, they are of very little 

 direct service. The Bog-mosses (Sphagna) are 

 employed by gardeners in the rearing of orchids, 



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