e
pinnae broader, bluish or greenish glaucous above, often crowded to
overlapping. The smooth cliff brake has a decidedly northern range, growing
from northern Vermont to Missouri, and northwestward, but found rarely, if
at all, in southern New England.

[Illustration: Dense Cliff Brake. _Cryptogramma densa_ (From Waters's
"Ferns," Henry Holt & Co.)]

(3) DENSE CLIFF BRAKE

_Cryptogramma densa. Pellaea densa_

Modern botanists are inclined to place the dense cliff brake and the
slender cliff brake under the genus _Cryptogramma_, which is so nearly like
_Pellaea_ that one hesitates to choose between them. The word Cryptogramma
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. Gaspe and Mt. Albert in the Province of
Quebec, Grey County, Ontario, and in the far west.

(4) SLENDER CLIFF BRAKE

_Cryptogramma Stelleri. Pellaea gracilis_

Fronds (including stipes) three to six inches long, thin and slender with
few pinnae. The lower pinnae 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.

[Illustration: Slender Cliff Brake. _Cryptogramma Stelleri_]

We have collected this dainty and attractive little fern on the limestone
cliffs of Mt. Horr, near Willoughby Lake, Vt. It grew in a rocky grotto
whose sides were kept moist by dripping water. How we liked to linger near
its charming abode high on the cliff! And we liked also to speak of it by
its pleasing, simple name, "Pellaea gracilis," now changed