Pleuromeia

Pleuromeia, genus of extinct lycopsid plants from the Triassic Period (about 251 million to 200 million years ago) and characterized by an unbranched trunk up to 2 metres (6.6 feet) tall. Unlike other arborescent lycopsids of the Carboniferous Period (about 359 million to 299 million years ago), such as Lepidodendron and Sigillaria, Pleuromeia had a four-lobed bulblike base rather than a branching underground rhizome. A crown of long, thin leaves persisted near the growing tip of the trunk. Leaves and leaf bases were lost from lower portions of the plant. Like its relatives, Pleuromeia reproduced by spores. Some species produced a single large cone at the trunk apex, and others may have produced many smaller cones. Nonetheless, the details of how Pleuromeia reproduced remain unclear. The genus was widely distributed, and specimens are known from Russia, Europe, China, and Australia.