Sigillaria

Sigillaria, a genus of fossil club-mosses, belonging ptobably to the order Selaginellaceae, which formed one of the chief types of the vegetation of the Coal-measures. They had large and lofty stems, either unbranched or diohotomous, covered with the scars of fallen leaves in vertical rows. The leaves were narrow, linear and sedge-like, reaching eighteen inches in length; but generally only the cushion of attachment is preserved. The roots, known as Stigmaria, are found in the fire-clay below coal-seams, and in the Devonian. They reach twenty or thirty feet in length, and are cylindric and dichotomous. Their outer surface is pitted with the scars of the rootlets, and they have a medulla and a vascular cylinder of scalariform tracheids, growth being apical. The cone of fructification, known as Sigillariostrobus, is rare. It resembles Lepidostrobus, that of Lepidodendron, and was probably heterosporous.