Portion of Lepidodendron
This illustration shows a portion of Lepidodendron. Lepidodendron is the generic name of a large and important group of plants which flourished principally in the Carboniferous period. The outer surface of the bark is marked by lozenge-shaped, scale-like markings, the leaf-cushions. These are arranged in dense spirals, which wind around the stems. Often, the narrow and pointed leaves are found, still adherent; they may also carry cones (lepidostrobi), which in form somewhat resemble those of the fir. The branches usually fork repeatedly, and were implanted on a massive stem which had a similar external sculpture. Some of these stems have been seen in the roofs of coal workings with a length of a hundred feet. Their roots are generally known as stigmaria. The Lepidodendra belonged to the Lycopodiaceæ, and have their nearest representatives in the diminutive club-mosses, which they resemble even in their superficial characters.