8 ON GENERA AND SPECIES. 
2,—ORGANOGRAPHY. 
DEFINITIONS OF THE PARTS OF FERNS ON WHICH GENERA ARE 
i FOUNDED AND CLASSIFIED, 
Frogs 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 ` 
TS (caudex), and before expansion are spirally coiled 
inwards (cireinate), 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 (synangia) cases, which contain | 
numerous microscopic germs, called spores (seed). The 
— [masses of spare cases are called sori. "They are either ` 
furnished with a special covering of various forms, called ` 
a 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 S 
presents two forms. First—Fasciculote 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 
