294 



HALF-HOURS IN THE GREEN LANES. 



seen the twisted peristome, so much resembling the 

 screwed end of an iron bolt, that you see at once 

 the origin of its name. This twisted appearance 

 also is seen on the " lid " (d). The leaves of most 

 mosses are very beautiful objects under the micro- 

 scope, the cellular structure coming out very 

 distinctly, and showing their six-sided shapes, due 

 to the mutual pressure induced by the growth of 



Fig. 221. 



Ceratodon purpwcus. a. Male Plant. 1. Leaf and its Areolation. 

 2. Capsule. 3. Calyptra. 4. Two Teeth of the Peristome. 



each cell. On the waste ground by the roadside 

 you may frequently find another species of moss 

 which, at first sight, you would take for the 

 Tortula muralis just described. That useful in- 

 strument, a good pocket-lens, however, will soon 

 rectify the mistake, and show you that it is quite 

 another genus of moss, called Ceratodon purpureus 

 (Fig. 221). In the woodcut are given the chief 

 parts of the moss as seen under a magnifying glass 



