CHAPTER IY. 
CLASSIFICATION. 
A deeply interesting study is here opened up for the lover 
of Ferns. These beautiful plants do not consist of a con- 
fused mass of individuals, possessing no resemblance to one 
another, and having no characters in common. They bear 
such distinct relationship to each other as to admit of their 
being arranged systematically into various large and small 
groups. 
If we regard the whole Fern world as itself hut a class in 
the sub-kingdom of cryptogamic plants, we shall find that this 
class will admit of being further divided, according to certain 
well-marked characters of the groups composing it, into orders. 
The orders, in turn, admit of further grouping into genera — 
singular genus, the latter into species, and species into 
varieties. Let us, for the moment, lose sight of the minute 
division of our flowerless plants into varieties, and regard 
only that aggregation of individual plants which is termed a 
species. A species, then, includes an assemblage of indi- 
viduals, which, generally speaking, may be said to closely 
resemble each other. The accidental circumstance of size may 
temporarily prevent actual or immediate resemblance. But 
it is assumed, for the sake of the comparison here instituted, 
that two individual plants of the same species, of the same 
age, and growing under precisely the same conditions, are 
alike. If between individuals so closely resembling each other 
there are certain minor, though well-defined and tolerably 
