INTRODUCTION. 37 
gradually becoming narrower towards each extremity : 
this form of frond is more or less the character of 
the Male Fern, the Lady Ferns, the Prickly Ferns, 
and most of that family of Ferns which the careless 
and superficial love to call “ Dilatatums.” 
The cutting or dividing of the frond is a cha- 
racter which admits of more minute description: when 
there is no division at all the frond is called “ entire,” 
and of this the Hart’s Tongue is the most familiar 
example: but when it is deeply notched along the — 
edge, the notches going in almost to the midrib or : 
mid-stem, it is called “ pinnatifid”; of this the com- 
mon Polypody is an example which you may find 
almost everywhere, and almost every day in the year. 
Going one step further, when the notches go quite 
to the midrib, and all the divisions are like distinct 
leaves, then the frond is said to be “pinnate,” and 
the divisions are called “pinnw”: of this the Holly 
Fern furnishes an excellent example. But these 
simple characters of outline, these “ entire,” “ pinnati- 
fid” or “pinnate” forms are not so common as more 
divided forms: the pinne are often divided, and their 
divisions are called “pinnulw” or “pinnules”; and 
