A fossilized root of a giant lycopod (plant), common in Carboniferous coal measures.
Class Lycopsida, in particular the genera Lepidodendron and Sigillaria
- ‘The round nodes on the surface of the stigmaria are scars where ribbon-like rootlets were once attached and arranged radially about the stigmaria like the bristles of a bottle brush.’
- ‘The rhizomes, or root systems, of both genera, known as stigmariae, were thought to be distinct plants when their fossils were first discovered.’
- ‘Stigmariae are most often found in layers of clay below coal seams; the clay layer is thought to represent the layer of soil below the coal swamps.’
Mid 19th century modern Latin, from Greek stigma, with reference to the scars where rootlets were attached, covering the fossils.