84 * HISTORY OF BRITISH PERNS. 
sight resemblance to a tuft of parsley, and is hence some¬ 
times called Mountain Parsley, grows in a dense tuft, 
throwing up its fronds in May or June, and losing them 
in the course of the autumn. The fronds average about 
six inches in height, and are generally somewhat three- 
cornered in outline, with a longish, slender, smooth stalk. 
They are of two kinds; both kinds being twice or thrice 
pinnate, and of a pale green-colour. The segments into 
which the sterile fronds are cut, are more or less wedge- 
shaped, and notched or cleft at the end. The fertile fronds 
have the segments of an oval or oblong, or linear form. 
The divisions of the fertile frond have a slightly tortuous 
midvein, producing simple or forked venules which extend 
nearly to the margin, each, for the most part, bearing near 
its extremity a circular sorus. There is no true indusium, 
but the sori are covered by the reflexed and partially 
bleached margins which sometimes almost meet behind, 
so that the spore-cases are quite concealed. These patches 
are at first distinct, but ultimately meet laterally, and 
become more or less blended together. 
The Rock Brakes is a mountain Fern, choosing to grow 
in stony situations. It is comparatively rare and local; 
most abundant in the north of England and Wales, and 
