The veins are free, and are forked or alternately divided into from two to five veinlets. The sori are rather large, placed nearer the midvein than the margin, and are rarely produced towards the apex of the segments. The indusium is orbicular-reniform, and almost always smooth. Its edges are turned downward, enclosing the sporangia, when they are young, and sometimes this convexity is permanent. Rarely the sinus is so deep that the indusium at last becomes divided. The spores are ovoid, and have a muricately roughened surface. The rhizomes have been used for ages as an anthelmintic, but probably have no greater virtue in this direction than those of many other common species. TRIFOLIATE CLIFF-BRAKE. CLAYTON’S CLIFF-BRAKE. SLENDER CLIFF-BRAKE. [Illustration: ] PELLÆA TERNIFOLIA, Link. Trifoliate Cliff-Brake. Pellæa ternifolia:—Root-stock short, thick, nodose, chaffy with very narrow dark-brown scales; stalks clustered, purplish-black and polished, three to six inches long; fronds as long as or longer than the stalks, oblong-linear; pinnæ from four to fifteen pairs, all but a few of the highest ones deeply tripartite; segments elongated-oval or linear-obovate, sub-coriaceous, somewhat glaucous beneath, green above, slightly mucronate, the middle one in large fronds indistinctly petiolulate; fertile ones with the edges much recurved; involucre broad, the edge only membranaceous. _Pellæa ternifolia_, Link, Fil. Hort. Berol., p. 59.—Fée, Gen. Fil., p. 129.—Hooker, Sp. Fil., i., p. 142; Fil. Exot., t. xv.—Fournier, Pl. Mex., Crypt., p. 118.—Eaton, Ferns of the Southwest, p. 321. _Pteris ternifolia_, Cavanilles, “Præl. 1801, No. 657.”—Hooker & Greville, Ic. Fil., t. 126. _Platyloma ternifolium_, J. Smith.—Brackenridge, Fil. U. S. Ex. Exped., p. 94. _Allosorus ternifolius_, Kunze, in Linnæa, xxiii., p. 220. _Pteris subverticillata_, Swartz, Syn. Fil., p. 103.—Willdenow, Sp. Pl., v., p. 375. Hab.—Texas, Trécul, No. 1334, according to Fournier. New Mexico, Wright, according to Hooker in _Filices Exoticæ_. The only specimens from Texas which I have of this species were collected by Dr. Sutton Hayes, near the headwaters of the Rio Colorado of Texas. It is a common Mexican species; it is found as far South as Peru, and reap pears in the Hawaiian Islands.