MOSSES. 



405 



blue stems, others orange, yellow, and green, with caps of various 

 colours, some of which are scarlet or crimson, and others have beau- 

 tiful shades of purple or violet. 



fig. 191. Screw Moss. 



fig. 192. Sccde Moss. 



The mosses are another low form of vegetable life ; and Linnseus 

 called them serm, — servants, or workmen, — as they seem to labour to 

 produce vegetation in newly-formed countries, where soil is not yet 

 formed. They also fill and consolidate bogs, and form rich mould for 

 the growth of larger plants, which they protect from the winter's cold. 

 The common or Wall Screw-moss, fig. 191, which grows 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 of which terminates in a dark brown case, which is, in fact, its 

 fruit. As the fruit ripens, a little cap, which covers it like an ex- 

 tinguisher, rises gradually, and is at last thrown ofi"; and when the 

 lid of the fruit, which is also conical, falls ofi", a curious tuft of twisted 

 hairs appears, forming a kind of fringe ; and it is from these twisted 

 hairs that the plant takes its popular name of Screw-moss. If a patch 

 of the moss is gathered when in this state, and the green part at 

 the base is put into water, the threads of the fringe will uncoil and 

 disentangle themselves in a most curious and beautiful manner, and 

 thus afibrd an opening to the seeds, which are exceedingly small, and 

 are contained within a thin bag, attached to the central column of the 

 case. It may here be mentioned, that all mosses and lichens are more 

 easily detached from the rocks and walls on which they grow in frosty 

 weather than at any other season, and consequently they are best stu- 

 died in winter. One of the commonest. Scale- moss, fig. 192 {Junger- 

 n/Mrmia bidentaia), grows in patches, in moist, shady situations, near 

 the roots of trees, upon commons, and on hedge-banks. The seed-ves- 

 sels are little oval bodies, which, if gathered when unexpanded, and 

 brought into a warm room, burst under the eye with violence the mo- 

 ment a drop of water is applied to them, the valves of the vessel taking 



