3. ADIÁNTUM, L. Maidenhair. ([Pl. 17.])
Fruit-dots marginal, short, borne on the under side of a transversely oblong, crescent-shaped or roundish, more or less altered margin or summit of a lobe or tooth of the frond reflexed to form an indusium; the sporangia attached to the approximated tips of the free forking veins.—Main rib (costa) of the pinnules none (in our species), or at the lower margin. Stipes black and polished. (The ancient name, from α privative and διαίνω, meaning unwetted, the smooth foliage repelling rain-drops.)
1. A. pedàtum, L. ([Pl. 17], fig. 1–3.) Frond forked at the summit of the upright slender stalk (9–15´ high), the recurved branches bearing on one side several slender spreading pinnate divisions; pinnules numerous, short-stalked and obliquely triangular-oblong, entire on the lower margin, from which the veins all proceed, and cleft and fruit-bearing on the other.—Rich, moist woods. July.—A delicate and most graceful Fern.
2. A. Capíllus-Véneris, L. Fronds with a continuous main rhachis, ovate-lanceolate, 9–18´ long, often pendent, 2–3-pinnate at the base, the upper third or half simply pinnate; pinnules wedge-obovate or rhomboid, 6–12´´ long, deeply and irregularly incised; veinlets flabellately forking from the base; involucres lunulate or transversely oblong.—Moist rocky places, Va. to Mo., and southward. (Eu.)
4. PTÈRIS, L. Brake or Bracken. ([Pl. 17.])
Sporangia in a continuous slender line of fructification, occupying the entire margin of the fertile frond, and covered by its reflexed narrow edge which forms a continuous membranaceous indusium, attached to an uninterrupted transverse vein-like receptacle connecting the tips of the forked free veins.—Fronds 1–3-pinnate or decompound. (The ancient Greek name of Ferns, from πτερόν, a wing, on account of the prevalent pinnate or feathery fronds.)
1. P. aquilìna, L. (Common Brake.) Frond dull green (2–3° wide), ternate at the summit of an erect stout stalk (1–2° high), the widely spreading branches twice pinnate; pinnules oblong-lanceolate; the upper undivided; the lower more or less pinnatifid, with oblong obtuse lobes, margined all round with the indusium, which is really double in this species.—Var. caudàta, with the lobes very narrow and revolute, the terminal ones much elongated, is a southern form, which extends in a modified condition as far north as New Jersey.—Thickets and hillsides, common. Aug. (Eu.)
5. CHEILÁNTHES, Swartz. Lip-fern. ([Pl. 17.])
Sporangia borne on the thickened ends of free veinlets, forming small and roundish distinct or nearly contiguous marginal fruit-dots, covered by a mostly whitish and membranaceous, sometimes herbaceous, common indusium, formed of the reflexed margin of separate lobes or of the whole pinnule.—Low, mostly with 2–3-pinnate and hairy or chaffy, rarely smooth fronds, the sterile and fertile nearly alike, the divisions with the principal vein central. Some species with continuous indusium connect this genus very closely with the next. (Name composed of χεῖλος, a lip, and ἄνθος, flower, from the shape of the indusium.)
[*] Fronds smooth, or at most hairy.