(2) SMOOTH CLIFF BRAKE
Pellàea glabella. Pellàea atropurpùrea, var. Bushii
Naked with a few, scattered, spreading hairs, smooth surface and dark polished stipes. Rhizome short with membranous, orange or brown scales having a few bluntish teeth on each edge. Pinnæ sub-opposite, divergent, narrowly oblong, obtuse; base truncate, cordate or clasping, occasionally auricled; lower pinnæ often with orbicular or cordate pinnules. Sterile pinnæ 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
Cryptográmma densa. Pellaèa densa
Modern botanists are inclined to place the dense cliff brake and the slender cliff brake under the genus Cryptográmma, which is so nearly like Pellaea that one hesitates to choose between them. The word Cryptográmma 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.