[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 for scientific reasons, but we still like the old name better.

(5) THE ROCK BRAKE.  PARSLEY FERN

Cryptogramma acrostichoides

Sterile and fertile fronds very dissimilar; segments of the fertile, linear and pod-like; of the sterile, ovate-oblong, obtuse, and toothed.  The plants spring from crevices of rocks and are from six to eight inches high.  Stipes of the fertile fronds are about twice as long as the sterile, making two tiers of fronds.

[Illustration:  Parsley Fern or Rock Brake. Cryptogramma acrostichoides (California and Oregon) (Herbarium of Geo. E. Davenport)]