Stigmaria
in palæobotany, a pseudo-genus of coal plants, now proved by actual union to be the roots chiefly of Sigillaria, but in some cases of Lepidodendron. Cylindrical, trunk-like bodies, often more or less compressed, the external surface of which is covered with shallow pits, sometimes with a rootlet projecting. Very abundant in the fireclay of the carboniferous rocks, the old soil in which the Sigillariæ grew. The common species is S. ficoides.