74 MOSSES AND LIVERWORTS 



to which I alluded when speaking of the mark- 

 ings on the peristome teeth (p. 71). Here, again, 

 the teeth sixteen in number are shutting down 

 over the capsule mouth, and so closely do they 

 fit together that sufficient space is not left be- 

 tween them even for the tiny spores to force a 

 passage. 



In not a few mosses the mouth of the capsule 

 is closed in a different manner. Plate V. fig. 3 

 gives the upper portion of the capsule of that 

 large-leaved, shade-loving moss that we have 

 already noticed as growing in the woods, or 

 on the shady banks of a country lane, the 

 Wavy-leaved Hair-moss (Catharinea undulata). 

 It will be seen, from the drawing, that the teeth 

 of the peristome are much shorter than those 

 which we have hitherto examined, so short, in 

 fact, that when closed they would not meet over 

 the mouth of the capsule. The same thing may 

 be seen even yet more clearly in the large brown 

 capsules of the Common Hair-moss (Polytrichum 

 commune], so plentiful on heathlands and commons, 

 for here the capsule mouth is very large, and the 

 teeth of the peristome sixty -four in number 

 are very small indeed. In such cases it would 

 at first sight seem as though Nature's object 

 had either been frustrated or that she had not 

 exercised the same amount of care to guard 

 against the too early escape of the spores, as in 

 so many other instances. A closer examination 



