Markings of Stem.—Leaf-bases long oval, pointed at ends, enlarging with growth of stem. Leaf-scars central, rhombic, transverse.
Leaves.—One-nerved, acutely pointed, from four inches in length on the larger branches to one inch or less on the branchlets.
Fructification.—Cones large, cylindrical or long oval, with large scales of trigonal form, and not elongated but lying close to the surface. Borne on lateral, slender branchlets, with short leaves.
Genus Lepidophloios, Sternberg; Ulodendron, L. and H.; Lomatophloios, Corda.
Lepidophloios.—Under this generic name, established by Sternberg, I include those lycopodiaceous trees of the coal-measures which have thick branches, transversely elongated leaf-scars, each with three vascular points and placed on elevated or scale-like protuberances, long one-nerved leaves, and large lateral strobiles in vertical rows or spirally disposed. Their structure resembles that of Lepidodendron, consisting of a Sternbergia pith, a slender axis of large scalariform vessels, giving off from its surface bundles of smaller vessels to the leaves, a very thick cellular bark, and a thin dense outer bark, having some elongated cells or bast-tissue on its inner side. In these trees the exogenous outer cylinder is less developed than in the Lepidodendra, and is sometimes wanting in stems or branches of some thickness.
Regarding L. laricinum of Sternberg as the type of the genus, and taking in connection with this the species described by Goldenberg, and my own observations on numerous specimens found in Nova Scotia, 1 have no doubt that Lomatophloios crassicaulis of Corda, and other species of that genus described by Goldenberg, Ulodendron and Bothrodendron of Lindley, Lepidodendron ornatissimum of Brongniart, and Halonia punctata of Geinitz, all belong to this genus, and differ from each other only in conditions of growth and preservation. Several of the species of Lepidostrobus and Lepidophyllum also belong to Lepidophloios.
The species of Lepidophloios are readily distinguished from Lepidodendron by the form of the areoles, and by the round scars on the stem, which usually mark the insertion of the large strobiles, though in barren stems they may also have produced branches; still, the fact of my finding the strobiles in situ in one instance, the accurate resemblance which the scars bear to those left by the cones of the red pine when borne on thick branches, and the actual impressions of the radiating scales in some specimens, leave no doubt in my mind that they are usually the marks of cones; and the great size of the cones of Lepidophloios accords with this conclusion.
The species of Lepidophloios are numerous, and individuals are quite abundant in the coal formation, especially toward its upper part. Their flattened bark is frequent in the coal-beds and their roofs, affording a thin layer of pure coal, which sometimes shows the peculiar laminated or scaly character of the bark when other characters are almost entirely obliterated. The leaves also are nearly as abundant as those of Sigillaria in the coal-shales. They can readily be distinguished by their strong, angular midrib.
The markings of Lepidophloios may easily be mistaken for those of the Clathraria type of Sigillaria. When the stem only is seen, they can be distinguished by the length of the leaf-bases in Lepidophloios, and by the dominant central vascular scar; also by the one-nerved and ribbed leaves. Where the large, round marks of the cones are present, these are an infallible guide, never being present in Sigillaria. As the cones grew on the upper sides of the branches, the impression of the lower side often shows no cone-scars, or only two lateral rows, whereas on the upper side of the same branch they appear spirally arranged. I may describe as an example—