MOSSES. 



309 



winter's cold. The common, or Wall Screw-moss, fig. 

 lo3, growing almost every where on old walls and other 

 brick-work, if examined closely, "will be found to have 

 springing from its base numerous very slender stems, each 



Fig. Wd.Screw Moss. 



of which terminates in a dark brown case, which encloses 

 its fruit. If a patch of the moss is gathered when in 

 this state, and the green part of the base is put into water, 

 the threads of the frin2;e will uncoil and disentansfle them- 

 selves in a most curious and beautiful manner ; from 

 this circumstance the plant takes its popular name of 

 Screw-moss. The leaf usually consists of either a single or 

 a double layer of cells, having flattened sides, by which 

 they aahere one to anotner. The 

 leaf-cells of the /Sphagnum bog- 

 moss, iig. 179, exhibit a very curi- 

 ous departure from the ordinary 

 type ; for instead of being small and 

 polygonal, they are large and elon- 

 gated, and contain spiral fibres 

 loosely coiled in their interior. Mr. 

 Huxley pointed out, that the young 

 leaf does not differ from the older^ 

 and that both are evolved by a 

 gradual process oV' differentiation.'''' 

 Mosses, like live,r worts, possess 

 both antheridia and pistillida, which „. 



■i . ^, '■ c J? Fi^. 164.— jl/ott/A of Capsule of 



are engaged m the process OI true- Funaria, showing peristome. 



tification. The fertilized cell be- 

 comes gradually developed into a conical body elevated 





