Labrador to Pennsylvania, usually on sheltered rocks, preferring limestone. Two to five inches long, with straw-colored or pale-brown stalks, slightly chaffy below.
Fronds.—Delicate, with few pinnæ; pinnæ, the lower ones once or twice parted into 3-5 divisions, those of the fertile frond oblong or linear-oblong, sparingly incised, of the sterile frond ovate or obovate, toothed or incised; sporangia bordering the pinnæ of the fertile frond, covered by a broad and usually continuous general indusium, formed by the reflexed margin of the pinnule.
The first time I found the Slender Cliff Brake was one July day in Central New York, under the kind guidance of an enthusiastic fern collector. A rather perilous climb along the sides of a thickly wooded glen brought us to a spot where our only security lay in clinging to the trees, which, like ourselves, had obtained doubtful standing-room. In a pocket in the limestone just above us I was shown a very brown and withered little plant which only the closest scrutiny in combination with a certain amount of foreknowledge could identify as the Slender Cliff Brake. The season had been a dry one and the plant had perished, I fancy, for lack of water, in spite of the stream which plunged from the top of the cliffs close by, almost near enough, it seemed to me, to moisten with its spray our hot cheeks.
Portion of fertile frond
Later in the season I found more promising though not altogether satisfactory specimens of this plant growing in other rocky crevices of the same deep glen, in the neighborhood of the Maidenhair Spleenwort, the Walking Leaf, and the Bulblet Bladder Fern.
My sister tells me that late in August on the cliffs which border the St. Lawrence River, refreshed by the myriad streams which leap or trickle down their sides, under the hanging roots of trees, close to clusters of quivering harebells and pale tufts of the Brittle Bladder Fern, the Slender Cliff Brake grows in profusion, its delicate fronds rippling over one another so closely that at times they give the effect of a long, luxuriant moss. On most occasions, in these soft beds of foliage, she found the fertile fronds, which are far more slender and unusual looking than the sterile, largely predominating, though at times a patch would be made up chiefly of the sterile fronds. These somewhat resemble the Brittle Bladder Fern in whose company they are seen so often.
Slender Cliff Brake