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Several hundred permineralized fragments of a single type of plant occur in upper Pennsylvanian coal balls from the Appalachian Basin, and these provide evidence for the description and complete reconstruction of a new heterosporous lycophyte. Chaloneria cormosa gen. et sp. nov. is unbranched, ca. 2 m tall, and has a rounded rooting base. Secondary xylem is abundant at the base, diminishes distally, and is absent from the apical region. The stem has ligulate microphylls that are vegetative at proximal levels and grade upward into a fertile apex. Leaf cushions are not produced. In the fertile zone there are alternating regions of megasporophylls and microsporophylls. A second species, Chaloneria periodica sp. nov., has alternating vegetative and fertile zones and is based on Middle Pennsylvanian specimens that were previously referred to Polysporia mirabilis. Spores of both species are assignable to …