GROUP III
FERTILE FRONDS UNIFORMLY SOMEWHAT LEAF-LIKE IN APPEARANCE, YET DIFFERING NOTICEABLY FROM STERILE FRONDS
15. SLENDER CLIFF BRAKE
Pellæ gracilis (P. Stelleri)
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 our-
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