We continue the prehistoric plant series with this fossil (noted to be about 22cm long), showing the branches and thin leaves of Lepidodendron lycopodioides. Thank you to the user Woudloper at Wikimedia Commons for the photo.
Lepidodendron species were a dominant plant species in the Carboniferous period, and lasted until the late Permian. Also called scale trees or giant club mosses, they used spores to reproduce and were tree-like in habit, growing over 30m tall with branches splitting in twos (an illustrated reconstruction). However, support for their large bodies came not from their wood, which only existed as a thin strand in the centre of the trunk, but from their thick bark. On their branches and trunks, Lepidodendron species had distinctive diamond-shaped scales called leaf cushions that denoted where leaves used to be (Andrews’ Studies in Paleobotany (1961)); these unique patterns are often seen as fossil impressions.
The arborescent lycopsids are known to have grown in peat swamps. Most of the coal deposits found in the eastern US and western Europe today originated from the bark of arborescent lycopsids. Different lycopsid genera are classified by the shapes of leaf cushions and position of vascular strands. Their closest living relatives appear to be the diminutive clubmosses and quillworts, groups of fern allies incomparable to the stature of Lepidodendron.