30 GENERAL CHARACTERS OP FERNS 'AND MOSSES. 



interesting than this, which requires neither skill, nor the assist- 

 ance of instruments, for the detection of its beauties. 



26. Although Ferns constitute but a comparatively small 

 part of the present vegetation of this country, they must have 

 been much more abundant in a former period of the eartlTs 

 history, especially at the time when the beds of coal were being 

 formed ; since their remains now constitute by far the largest 

 part of those, which are preserved to us with tolerable perfection 

 in a fossil state. This is partly due, however, to the remarkable 

 power which these plants possess, of resisting the action of water ; 

 by which other plants and trees were decomposed, their remains 

 having contributed to form those immense masses of Coal, which 

 are so important to Man, not only for his personal comfort, but 

 for the arts of life. The Ferns are able to withstand the effects 

 of even a very prolonged immersion in water, with scarcely any 

 change ; whilst not only the soft tissue of plants, but the heart- 

 wood of most trees, decays so completely under the same circum- 

 stances, as to leave little or no traces of their character. In tro- 

 pical islands, the Ferns constitute a most important part of the 

 whole vegetation ; being equal in number, in the Sandwich 

 Islands, to one-fourth, and in Jamaica to one-ninth, of all the 

 Flowering-plants existing in each of these localities. 



27. The next principal group of Cryptogamia,that of Mosses, 

 is as interesting from the delicacy and minuteness of all the plants 

 composing it, as other tribes of the Vegetable Kingdom are for 

 the majesty of their forms, or the vast extension of their foliage. 

 These are so generally and easily recognised as such, that a minute 

 description of them is at present unnecessary ; but it should be 

 stated that the term Moss is commonly applied, not only to the 

 true Mosses, but also to many Lichens. The true Mosses, how- 

 ever, are always to be known, by the green colour they possess, 

 except when dried up ; while the Lichens are usually grayish in 

 their aspect. Mosses usually possess a sort of stem, round which 

 the minute leaves are arranged with great beauty and regu- 

 larity ; but neither this stem, nor the leaf-stalks of the leaves, 

 have any truly woody structure ; and they more, closely resemble 

 the simple tissue of the lowest plants, than the complex fabric 



