28 



GENERAL CHARACTERS OF FERNS. 



and other temperate countries, is well known. They present a 

 small number of leaves, generally much divided into leaflets, and 

 these again often minutely subdivided, each arising from the 

 ground by a woody stalk, which is commonly regarded as the 

 stem of the plant. The true stem, however, is buried beneath 

 the ground, or sometimes creeps along its surface ; and the 

 branches it sends upwards into the air, are really the leaf-stalks. 

 (Fig. 2). In many Ferns of tropical climates, the true stem 

 rises upright, like that of a tree, and bears at the top a beautiful 

 crown of those peculiarly graceful leaves, for which th~ Ferns 

 are remarkable. The height of these Tree Ferns, which are 

 most luxuriant in the small islands, where they are furnished 



Fro. 2. POLYPOUIUM VUL- 



OARE, COMMON POLYPODY, 



OR WALL FERN. 



FIG. 3. TREE FKRV. 



with a more regular supply of atmospheric mo'sture than they 

 can obtain at a greater distance from the sea, is sometimes as 



