WALKING-LEAF.
PINNATIFID SPLEENWORT.
CAMPTOSORUS RHIZOPHYLLUS, Link.
Walking-Leaf.
Camptosorus rhizophyllus:—Root-stock short, creeping or ascending; stalks tufted, slender, flaccid, green, but becoming brown near the base; fronds a few inches to a foot long, sub-coriaceous, evergreen, smooth, gradually narrowed from a deeply cordate and auricled base to a long and very slender prolongation, decumbent and often rooting at the end; veins reticulated near the midrib, and having free apices along the margin; sori elongated, variously placed on either side of the veins, often face to face in pairs, or extending around the upper part of the meshes; indusium delicate.
Camptosorus rhizophyllus, Link, Hort. Berol., ii., p. 69; Fil. Sp. Hort. Berol., p. 83.—Presl, Tent. Pterid., p. 121, t. 4, fig. 8.—Hooker, Gen. Fil., t. 57, C; Fil. Exot., t. 85.—Gray, Manual.—Darlington, Flora Cestr., ed. iii., p. 393.—Mettenius, Fil. Hort. Lips., p. 67, t. 5, fig. 6.
Asplenium rhizophyllum, Linnæus, Sp. Pl., p. 1536.—Swartz, Syn. Fil., p. 74.—Willdenow, Sp. Pl., v., p. 305.—Michaux, Fl. Bor. Am., ii., p. 264.—Bigelow, Fl. Boston.
Antigramma rhizophylla, J. Smith, in Hook. Journ. Bot., iv., p. 176; Ferns, British and Foreign, p. 226.—Torrey, Fl. New York, ii., p. 494, t. 159 (Asplenium).
Scolopendrium rhizophyllum, Endlicher, Gen. Pl., Suppl. i., p. 1348.—Hooker, Sp. Fil., iv., p. 4.—Hooker & Baker, Syn. Fil., p. 248.
Hab.—On mossy rocks, especially limestone. Not uncommon from Canada to Virginia and Alabama, and westward to Wisconsin and Kansas. It occurs in many places in Western New England, but is rare to the east. It has lately been found a few miles from Boston; but there is a doubt whether the station is truly natural.
Description.—The walking-leaf is usually found in patches of considerable extent. It seems to prefer mossy calcareous rocks, and the finest specimens are usually firmly rooted in the crevices. In Cheshire, Connecticut, it grows freely on moist cliffs of sandstone bordering a deep ravine; and in Orange, in the same State, it is found on scattered ledges of serpentine. The root-stock is very short, but creeping: it bears a few dark-fuscous scales, and is covered with the remains of decayed stalks. A few fronds grow from the end of the root-stock, and are supported on slender herbaceous stems a few inches long. A transverse section of the lower part of the stalk is semicircular, and shows a very slender triangular central thread of dark sclerenchyma, with two somewhat roundish fibro-vascular bundles close beneath or behind it. A section higher up shows that the stalk is there narrowly winged on each side, and the two fibro-vascular bundles have coalesced into one of a roundish-triangular shape. The frond is long and narrow, and rarely rises erect, but usually is decumbent or reclined in position.