32 HISTORY OF BRITISH FERNS. 



warmer regions is less great, but their influence on the 

 aspect of vegetation there is of a different character ; they 

 are more frequently parasitic in the tropics, and by their 

 varied forms and colours, and the way in which they fix 

 themselves, they give an air of peculiar luxuriance to the 

 higher vegetation. Even in the temperate regions some of 

 these herbaceous Eerns attain considerable height, as is the 

 case with the common Bracken, which, in the hedge-rows of 

 sheltered rural lanes in the south of England, reaches the 

 height of eight or ten feet, and assumes the most graceful 

 habit that can be conceived. 



Wherever the Eerns occur, whether it 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 luxuri- 

 ance to the scenery, and that to an extent which is not 

 realized by any other race of plants. 



