Sprecher
Beschreibung
Cordaitales represent an extinct group of cosmopolitan gymnosperms with a chronostratigraphic range from the Mississippian to the Permian. These plants are commonly interpreted as having monopodial trunks that reached considerable heights before developing a crown of branches bearing sessile, elongated leaves often arranged in a spiral pattern. The group includes arborescent forms, known from tropical Pennsylvanian deposits that frequently exceeded 30 m in height, as well as smaller forms, including scrambling shrubs and small trees. Cordaitalean axes exhibit a particularly complex internal structure concerning their pith, which may be septate and parenchymatous in mature plants. Although less frequent, such kind of pith also occurred in other Paleozoic plants, making the taxonomic assessment of isolated pieces of wood challenging. Despite the recurrence of septate and parenchymatous piths among Paleozoic paleoxylofloras, their structural organization, maturation, and possible functional significance in cordaitalean axes remain poorly understood. This study investigates the anatomical structure of the pith in cordaitalean axes based on classical literature and fossil material from the Permian fossil forests of Chemnitz in central Germany and the Parnaíba Basin in northeastern Brazil. Based on the available literature, studies on connected organs, seven samples previously classified as Cordaixylon Grand'Eury 1877 from the Parnaíba Basin, and one specimen from the Chemnitz Basin, we conducted a detailed analysis of pith types in Cordaitales, aiming to better understand pith composition, ontogeny, and possible functional implications. The recurrence of septate piths among distinct Paleozoic gymnosperm groups raises the possibility of convergent anatomical responses associated with similar paleoenvironments.