Var. Clintoniànum. Frond in every way much larger (2½–4° long); pinnæ oblong-lanceolate, broadest at base (4–6´ long, 1–2´ broad), deeply pinnatifid; the divisions (8–16 pairs) crowded or distant, linear-oblong, obtuse, obscurely serrate or cut-toothed, the basal sometimes pinnately lobed; veins pinnately forking, the lowest anterior veinlets bearing the fruit-dots near the midvein; indusium orbicular with a shallow sinus, smooth and naked.—Swampy woods, New Eng. to N. J., N. Y. (G. W. Clinton, etc.), and westward. July.—Rootstock stout, creeping, chaffy (like the stipes) with large bright-brown scales. A showy fern, unlike any European form of A. cristatum, and often mistaken for A. Goldianum.
7. A. Goldiànum, Hook. Frond broadly ovate, or the fertile ovate-oblong in outline (2–3° long); pinnæ (6–9´ long), oblong-lanceolate, broadest in the middle, pinnately parted; the divisions (about 20 pairs) oblong-linear, slightly scythe-shaped (9–15´´ long), serrate with appressed teeth; veins pinnately forking and bearing the fruit-dots very near the midvein; indusium very large, orbicular with a deep narrow sinus, smooth and without marginal glands.—Rich and moist woods, from Conn. to Ky., and northward. July.—A stately fern, often 4° high, the fronds growing in a circle from a stout ascending chaffy rootstock, and decaying in autumn. Indusium with the sides of the sinus often overlapping, thus appearing to be round and entire as in § Polystichum.
[+][+][+][+] Large (1–3° high); stipes very chaffy at base; fronds twice pinnate, but the upper pinnules confluent, some of the lower pinnatifid-toothed; fruit-dots rather large; indusium convex, without marginal glands, persistent.
8. A. Fílix-mas, Swartz. Frond lanceolate in outline (1–3° high); pinnæ linear-lanceolate, tapering from base to apex; pinnules oblong, very obtuse, serrate at the apex and obscurely so at the sides, the basal incisely lobed, distinct, the upper confluent; fruit-dots nearer the midvein than the margin, and usually confined to the lower half of each fertile pinnule.—Rocky woods, N. Mich. to Dak. and Col.—Frond thickish but not surviving the winter. (Eu.)
9. A. marginàle, Swartz. ([Pl. 19], fig. 1, 2.) Frond evergreen, smooth, thickish and almost coriaceous, ovate-oblong in outline (1–2° long); pinnæ lanceolate, acuminate, slightly broadest above the base; pinnules oblong or oblong-scythe-shaped, crowded, obtuse or pointed, entire or crenately-toothed; fruit-dots close to the margin.—Rocky hillsides in rich woods; common, especially northward. Aug.
§ 2. POLÝSTICHUM. Indusium orbicular and entire, peltate, fixed by the depressed centre; fronds rigid and coriaceous, evergreen, very chaffy on the rhachis, etc.; pinnæ or pinnules auricled at base on the upper side, crowded, the teeth or lobes bristle-tipped.
[*] Fronds simply pinnate.
10. A. acrostichoìdes, Swartz. (Christmas Fern.) ([Pl. 19], fig. 3, 4.) Frond lanceolate (1–2½° high), stalked; pinnæ linear-lanceolate, somewhat scythe-shaped, half-halberd-shaped at the slightly stalked base, serrulate with appressed bristly teeth; the fertile (upper) contracted and smaller, bearing contiguous fruit-dots near the midrib, which are confluent with age, covering the surface.—Var. incìsum is a state with cut-lobed pinnæ, a not unfrequent case in the sterile fronds; sometimes with all the tips fertile.—Common in rocky woods, especially northward. July.
11. A. Lonchìtis, Swartz. Frond linear-lanceolate (9–20´ high), scarcely stalked, very rigid; pinnæ broadly lanceolate-scythe-shaped, or the lowest triangular, strongly auricled on the upper side, and wedge-truncate on the lower, densely spinulose-toothed (1´ or less in length), copiously fruit-bearing; fruit-dots contiguous and near the margins.—Woods, southern shore of Lake Superior, and northward. (Eu.)
[*][*] Fronds bipinnate.