DISTRIBUTION AND TOPOGRAPHICAL ASPECT. 35 



in warmer regions is less great, but their influence on the 

 aspect of vegetation there is of a different character. They 

 are frequently epiphytal in the tropics, and by their varied 

 forms and tints, and the way in which they fix themselves, 

 they give an air of peculiar luxuriance to the higher vege- 

 tation. Even in the temperate regions some of these 

 herbaceous Ferns attain considerable height, as is the case 

 with the common Bracken, which, in the hedgerows of 

 sheltered rural lanes in the south of England, reaches the 

 heio-ht of eight or ten feet, and assumes the most graceful 

 habit that can be conceived. 



Wherever the Ferns occur, whether they be the herbaceous 

 species of temperate climates, or the arborescent species of 

 the equatorial regions, or the epiphytal species which clothe 

 the trunks and branches of the trees in tropical forests, 

 they add a marked and peculiar character of beauty and 

 luxuriance to the scenery, and that to an extent which is 

 net realized by any other race of plants. 



D 2 



