5 P. Dryopteris L. Ternate Polypod. Frond ternate, bipinnate; branches of the frond spreading, deflexed, segments obtuse, subcrenate; sori marginal; root filiform, creeping. - This beautiful fern grows in shady places and mountainous woods, common North. Root black and very slender. Stipe slender and delicate, smooth, nearly a foot high, dividing into 3 light green, drooping, compound leaflets of a very delicate texture. Jl.
β. calcareum. Branches of the frond erect, rather rigid. (P. calcarcum Sm.)
8. STRUTHIOP'TERIS, Willd. Ostrich Fern. (Gr. an ostrich, a fern.) Fertile fronds contracted, the margins rolled backwards and covering the round, confluent sori, which are otherwise without an indusium. - Fronds bipinnatifid, the fertile pinnae moniliform linear.
S. Germanica Willd. A Fern of noble port, in low woods and swamps, N. States and Can., common. The sterile fronds are often 5 or 6f high, commonly about 3f, numerous, in a circular clump. Stipes smooth, channeled. Pinnae numerous, crowded, long, linear, each with numerous oblong segments of which the lowest is longer and acute, all more or less connected at base. Fertile fronds few in the midst of the sterile, much smaller, the pinnae subterete, 1 to 2' long, crowded. Sori about 5 in each segment, on the raised ends of as many veinlets. Aug.
9. PTE'RIS, L. Brake. Rock Brake. (Gr. a wing.)
Sori borne on the ends of the veins forming a marginal line, covered with the membranous, reflected edge of the frond. - Fronds once to thrice pinnate or decompound.
§ Frond pedate, or ternate and bipinnatifld. Sori in a continuous line........
§ Frond partly bipinnate. Sori at first distinct but soon continuous......................................
1 P. aquilina L. COMMON Brake. Frond 3-parted; branches bipinnate; Ifts. oblong-lanceolate, lower ones pinnatifid, upper ones entire; segments oblong, obtuse. - Abundant in woods, pastures and waste grounds. Fern 2 - 5f in height, upon a smooth, dark purple, erect stipe. Frond broad-triangular in outline, consisting of 3 primary divisions, which are again subdivided into obtusely pointed, sessile leaflets. These are entire above, becoming gradually indented towards the base of each subdivision. Sori covered by the folding back of the very margins of the segments.
β. caudata. Segm. of the pinnae linear oblong, the terminal one much elongated. - The common Southern form.
2 P. pedata Willd. Frond ternately parted, the lateral divisions 2-parted, all pinuatifid; segm. linear-lanceolate, acute, the lowest segment of the terminal division pinnatitid; terminal division long-cuneiform at base, recesses acute. - On rocks, Va. (Pursh). Fern about 6' high.
3 P. atropurpurea L. Rock Brake. Frond pinnate; rachis hairy; lower lfts. ternate or pinnate, segments lance-oblong, obtuse, obliquely truncate or sub-cordate at the petiolate base. - Fern 6 - 10' high, growing on rocks, Can., Wis.. Wt. to Tenn.! and Ala.! Frond twice as long as wide, of a grayish hue, the two lower divisions consisting of 1 - 3 pairs of leaflets with a long, terminal segment. All the segments distinct, with margins conspicuously revolute. Some of the larger have 1 or 2 auricles at base. Stipe and rachis dark purple, with dense, paleaceous hairs at base. June - Aug. (Allosorus, Gr. P. Alabamensis Buckley, when the upper segments are generally auricled.)
4 P. gracilis Michx. Frond slender, lanceolate, sterile ones pinnate, leaflets pinnatifid, segments broad-ovate, obtuse; fertile bipinnate, leaflets linear-oblong, crenate. - A delicate species, growing on rocks. Fern 4 - 6' high, smooth and shining throughout. Both this and No. 3 are homogeneous in habit with the others. Their separation to a new genus is an over-refinement. (Allosorus, Presl.)
10. CHEILAN'THES, Swartz. Lip Fern. (Gr. a lip, ; from the form of the indusia.) Sori roundish, distinct, situated at the margin or apex of the segments; indusia distinct, formed from the reflected margin and opening inwards. - Segments of the frond with the midvein central.
1 C. vestita Swartz. Stipe and rachis hairy; frond bipinnate, oblong-ovate in outline, hairy on both sides; leaflets alternate; segments oblong, alternate, sessile, distinct, crenately pinnatifid, the ultimate segment very entire; sori distinct, their indusia unchanged. - Rocky banks, Penn. to Mo. and South. Stipe slender, rigid, 2 - 3' long, dark brown. Fronds 3 - 6' by 1 - 2'. Leaflets lance-ovate in outline, 6 - 12" long. A small and delicate, hairy Fern. Jl.
2 C. tomentosa Link. Stipe stout, and with the rachis and frond clothed with a dense ferruginous wool; frond tripinnate, ultimate segments rounded or oblong, obtuse (upper ones confluent), fruit-bearing around the whole margin. - N. Car. (Curtis) and Tenn. Fern If to 18' high, much larger and more hairy than the preceding. Both species are less hairy on the upper than the under surface.
11. ADIAN'TUM L. Maiden-hair. (Gr. a, privative, to moisten; as the rain slides off without wetting it.) Sori oblong or roundish, marginal; indusia membranaceous, formed from the reflexed margins of distinct portions of the frond and opening inwardly. - Stipe polished. Ultimate segments dimidiate, the midvein on the lower margin.
1 A. pedatum L. Frond pedate: divisions pinnate; segments oblong-rhomboid, incisely lobed on the upper side, obtuse at apex; sori oblong, subulate. - This is, doubtless, the most beautiful of all our ferns, abounding in damp, rocky woods. Stipe 8 - 14' high, slender, of a deep, glossy purple approaching to a jet-black. At top it divides equally into 2 compound branches, each of which gives off, at regular intervals, 6 - 8 simply pinnate leaflets from the outer side, giving the whole frond the form of the crescent. July.