S4 HISTORY OF BRITISH FERNS. 



marks left on the falling away of the fronds ; they grow 

 to a height of from twenty to fifty feet or more, from their 

 tops sending out the feathery fronds, often many feet iu 

 length, and yet so delicate as to be put in motion by the 

 gentlest breeze. On some of the East-Indian Islands the 

 tree Ferns are said to occur as numerously as the crowded 

 Firs in our plantations ; but wherever they are found — 

 from the plains to an elevation of 3000 to 4000 feet — 

 the soil and atmosphere are full of moisture. Very noble 

 arborescent Ferns are also found in New Zealand and 

 Tasmania. 



The shrubby Ferns, those with short stems, surmounted 

 by tufted fronds, prevail rather at the tropics tho.n at the 

 C(|uatorial zone, and are found less frequently at the foot 

 of tropical mountains than at an elevation of from 2000 to 

 SOOO feet. Ferns of this aspect abound in the South Sea 

 Islands. Mr. Colcnso describes one of the New Zealand 

 species as producing, from a main trunk twelve feet high, 

 fronds which form a droop often of eighteen feet ; such 

 plants, standing singly on the bank of a stream, being 

 objects of surpassing beauty. 



Tlie dwarf herbaceous species arc rather characteristic 

 of the temperate and colder zones : not that their number 



