MOSSES. LIVERWORTS. 33 



the oniy things, which seem to enjoy the clouds and storms of 

 the season. They choose the most exposed situations, spread 

 out their leaves, and push up their delicate urns, amidst rain, 

 frost, and snow ; and yet there is nothing in their simple and 

 tender structure, from which we could infer their capability of 

 resisting influences so generally destructive to vegetation. But 

 it is with Plants as with Animals. The more simple and lowly 

 the being, the greater is usually its tenacity of life, under cir- 

 cumstances which depress the vital powers of higher kinds; 

 whilst the influences which they require are often too powerful 

 for it. Thus, Mosses and Lichens, over-stimulated by heat and 

 dryness, wither away in summer; but vegetate freely at a season 

 when there is no other vegetation, and when their humble fabrics 

 cannot be overshadowed by a ranker growth. 



31. Mosses were fancifully termed by Linnasus, servi, serv- 

 ants, or workmen ; for they seem to labour to produce vegeta- 

 tion in newly-formed countries, where soil can scarcely yet be 

 said to be. This is not their only use, however. They fill up 

 and consolidate bogs, and form rich vegetable mould for the 

 growth of larger plants, which they also protect from cold during 

 the winter. They likewise clothe the sides of lofty hills and 

 mountain-ranges ; and powerfully attract and condense the 

 watery vapours floating in the atmosphere, and thus become the 

 living fountains of many streams. They are sometimes so c6m- 

 pletely dried up by drought, that they escape notice ; and then, 

 when moistened by rain, they appear to have suddenly clothed a 

 barren heath, or overspread a dry wall with verdure, on which, 

 however, they really existed before. 



32. Closely con- 

 nected with the Mosses 

 is the tribe of Hepaticce, 

 or Liverworts, the lower 

 forms of which are near- 

 ly connected with the 

 Lichens. Some of them 

 differ but little in their 

 general characters from F '- &-HWATIC*. OR LIVEKWOHTS. 



