ON GENERA AND SPECIES. 



2. ORGANOGRAPHY. 



DEFINITIONS OF THE PARTS OF FERNS ON WHICH GENERA ARE 

 FOUNDED AND CLASSIFIED. 



FILICES or Ferns are flowerless plants, and form the highest 

 order of the division of the Vegetable Kingdom termed 

 Cryptogamia, which includes all plants having their organs 

 of reproduction invisible to the naked eye. They have no 

 true leaves, but produce leaf-like expansions, called fronds, 

 which not only perform the functions of leaves, but also 

 bear the organs of reproduction. The fronds are succes- 

 sively developed from the apex or sides of an accrescent 

 stem (caudex), and before expansion are spirally coiled 

 inwards (circinate). They are traversed by veins in various 

 ways, and produce on their under surface, or on special 

 appendages, round linear, or irregular masses of one-celled 

 (sporangia) or many celled (synanyia) cases, which contain 

 numerous microscopic germs, called spores (seed). The 

 masses of spare cases are called son'. They are either 

 furnished with a special covering of various forms, called 

 the indusium (indusiate), or they are naked (non-indusiate) . 



VERNATION (STEMS). 



The manner in which the fronds are developed from 

 their axis is termed vernation, and their union with the 

 axis is either adherent or articulate. Adherent vernation 

 presents two forms. First Fasciculate when the fronds are 

 produced in a continuous spiral whorl from the apex of the 

 axis with which their bases are adherent, and thus by their 



