means in Greek a _hidden line_, alluding to the line of sporangia hidden
beneath the reflexed margin.

The dense cliff brake may be described as follows:

Stipes three to nine inches tall, blades one to three inches,
triangular-ovate, pinnate at the summit, and tripinnate below. Segments
linear, sharp-pointed, mostly fertile, having the margins entire and
recurved, giving the sori the appearance of half-open pods. Sterile
fronds sharply serrate. Stipes in dense tufts ("_densa_") slender, wiry,
light-brown.

This rare little fern is a northern species and springs from tiny crevices
in rocks, preferring limestone. Like many other rock-loving species, it
produces spores in abundance, having no other effective means of spreading,
and its fertile fronds are much more numerous than the sterile ones, and
begin to fruit when very small. Gaspé and Mt. Albert in the Province of
Quebec, Grey County, Ontario, and in the far west.


(4) SLENDER CLIFF BRAKE

_Cryptográmma Stellèri. Pellaèa grácilis_

Fronds (including stipes) three to six inches long, thin and slender with
few pinnæ. The lower pinnæ pinnately parted into three to five divisions,
those of the fertile fronds oblong or linear-oblong; those of the sterile,
obovate or ovate, crenulate, decurrent at the base. Confined to limestone
rocks. Quebec and New Brunswick, to Vermont, Connecticut, Pennsylvania, and
to the northwest.