Fruit-dots roundish or elongated and extending far down on the free forking veins. True involucre or indusium none, the herbaceous margins of the fertile segments at first reflexed and meeting at the midrib, at length opening out flat and exposing the confluent sporangia.—Low ferns, with smooth, 2–3-pinnate fronds, the fertile ones taller than the sterile, and with much narrower divisions. (Name from κρυπτός, hidden, and γραμμή, a line, alluding to the lines of sporangia at first concealed by the reflexed margin.)
1. C. acrostichoìdes, R. Brown. Stipes densely tufted, straw-colored; fronds 2–3-pinnate (6–10´ high); fertile segments stalked, linear or linear-oblong (3–5´´ long), the sporangia in lines extending down the veins almost to the midrib, confluent when ripe and covering the under surface of the now fully opened segments; sterile fronds on much shorter stipes, with ovate or obovate decurrent and crenately toothed or incised segments. (Allosorus acrostichoides, Sprengel.)—On rocks, from L. Superior westward and northward.—Very near C. crispa of Eu.
8. WOODWÁRDIA, Smith. Chain-fern. ([Pl. 17.])
Fruit-dots oblong or linear, arranged in one or more chain-like rows on transverse anastomosing veinlets parallel and near to the midrib. Indusium fixed by its outer margin to the fruitful veinlet, free and opening on the side next the midrib. Veins more or less reticulated, free toward the margin of the frond.—Large ferns, with pinnatifid or pinnate fronds. (Named for Thomas J. Woodward, an English botanist.)
§ 1. ANCHÍSTEA. Sterile and fertile fronds alike; veins forming only one row of meshes (areoles).
1. W. Virgínica, Smith. ([Pl. 17], fig. 4, 5.) Fronds (2–3° high) pinnate, with numerous lanceolate pinnatifid pinnæ; segments oblong; veins forming a row of narrow areoles along the midrib both of the pinnæ and of the lobes, the outer veinlets free; fruit-dots oblong, one to each areole, confluent when ripe.—Wet swamps, Maine to Ark., and southward. Rootstocks creeping, often 6–8° long! July.
§ 2. LORINSÈRIA. Sterile and fertile fronds unlike; veins of the sterile fronds forming many rows of meshes.
2. W. angustifòlia, Smith. ([Pl. 17], fig. 1–3.) Fronds pinnatifid; sterile ones (12–18´ high) with lanceolate serrulate divisions united by a broad wing; fertile fronds taller, with narrowly linear almost disconnected divisions, the areoles and fruit-dots (4–5´´ long) in a single row each side of the secondary midribs; rootstocks creeping.—Wet woods, New Eng., near the coast, to Ark., and southward; rare. Aug., Sept.
9. ASPLÈNIUM, L. Spleenwort. ([Pl. 18.])
Fruit-dots oblong or linear, oblique, separate; the straight, or rarely curved, indusium fixed lengthwise by one edge to the upper (inner) side of the fertile vein;—in some species a part of the fruit-dots are double, the fertile vein bearing two indusia placed back to back. Veins free in all our species. (Name from α- privative and σπλήν, the spleen, for supposed remedial properties.)