72 MOSSES AND LIVERWORTS 



and ponds, often attaining a very considerable 

 length. I have seen its slender dark green 

 tresses streaming out from some stake in a river 

 to which they were attached, to the distance of 

 a couple of feet at least. When thus living in 

 the water it seldom fruits ; hut if, as sometimes 

 happens in a season of drought, it is left on the 

 mud hy the side of a pool, or on the hank of a 

 stream, the capsules will often he produced in 

 abundance, and such an opportunity of obtaining 

 objects for microscopical examination is one not 

 to be missed. 



The inner peristome in this instance can hardly 

 he said, in any sense, to be formed of teeth. In 

 the microscope it has all the appearance of being 

 composed of a number of fairy ladders set on 

 end. In the outer fringe the teeth are long and 

 much broader, thus strikingly setting off the deli- 

 cate inner structure. When seen in the microscope 

 the whole forms an object of extreme beauty. 



On the other hand, some mosses though they 

 are in a distinct minority have no peristome 

 (Plate IV.b, fig. 15), and then, of course, the 

 spores are free to escape on the fall of the lid. 



Plate V. fig. 5 will perhaps help to explain more 

 clearly the manner in which the peristome acts. It 

 represents a slice cut off the end of one of the 

 tiny round capsules of the Common Apple-moss 

 (Bartramia pomiformis) (see page 48). This has 

 been mounted so as to enable us to look down 



