GENERAL DESCRIPTION. 
In the broad primary division of the great Vegetable 
Kingdom into Flowering and Flowerless Plants, 
FERNS are placed at the head of the second class. 
Possessing a distinct stem and leaves (the latter 
named fronds, to distinguish them from the leaves of 
other plants), they are without flowers , ordinarily so 
called , and consequently cannot produce seeds in the 
ordinary flower-manner. They have also a special 
structure: for while the Flowering Plants are either 
Exogens — (plants whose stems consist of pith, wood, 
and bark, growing in concentric circles, and whose 
leaves have veins branching like net-work),—or Endo- 
GENS — plants without distinction of pith or bark, 
whose stems are merely confused pithy matter or 
woody fibrous thread-like bundles, and whose leaf- 
veins are parallel,—the Flowerless Plants, called Ac- 
rogens, have their wood disposed in a zigzag manner , and 
their leaves are either without veins , or with veins of the 
most simple character , scarcely branching at all, or 
branching only in repeated forks. The greater outer 
distinction, however, is that of the absence of any ap- 
