THE STRUCTURE OF EERNS« 
15 
term flower in its popular sense, without entering into 
points of speculative botany), so that it is in the fronds 
that we must seek for that ornamental aspect which renders 
them such general favourites. The fronds alone, however, 
afford almost endless variety : — some are very large, others 
very small ; some quite simple and not at all divided, 
others divided beyond computation into little portions or 
segments, and it is these much-divided fronds which, 
generally speaking, are the most elegant. 
Even in the few species which are natives of Britain, 
this variety of size and form is very obvious, some kinds 
not being more than two or three inches, others five to six 
feet or more in height, — some quite simple, and others cut 
into innumerable small segments. There is much variety 
of texture too ; some being thin and delicate, almost trans- 
parent, others thick and leathery, and some perfectly rigid ; 
while as to colour, some are pale green, some are deep 
green, some are blue-green, some dark brownish, scarcely 
green at all ; and as regards their surface, some are smooth 
and shining, others opaque, and some few are covered with 
hair-like scales. 
The duration of the fronds of many species is compara- 
tively short : they come up in spring, and in some cases 
