Cordaitalean Seed Plants From the Early Permian of North China. Ii. Reconstruction of Cordaixylon Tianii

From a single Early Permian locality in the Taiyuan Formation of northern China, a new whole-plant cordaitalean is reconstructed and named Cordaixylon tianii ( B. Tian and S.-J. Wang) S.-J. Wang and J. Hilton sp. nov. The reconstruction is based on pairs of plant organs found in organic attachment, supplemented with cases where two or more co-occurring morphospecies share distinctive anatomical features. Stems have sympodial primary vascular architecture with endarch primary xylem maturation of the cauline bundles, which surround a septate pith. Leaf traces are endarch, most diverging from the pithmargin as double bundles ( less frequently singly) and bearing leaves in 3/8 and 5/13 phyllotaxis. Leaves are long and straplike, resembling those of the previously reconstructed Cordaixylon dumusum Rothwell and S. Warner, but with a geniculate posture that justifies their segregation as Cordaites tianii S.-J. Wang and J. Hilton sp. nov. Both male and female cones are compound, borne irregularly as epicormic branches, and when isolated conform to the morphogenus Cordaitanthus. Pollen cones with numerous pollen organs borne on apically concentrated fertile scales are largely consistent with the morphospecies Cordaitanthus concinnus Delevoryas, but subtle distinctions permit their description as C. tianii S.-J. Wang and J. Hilton sp. nov. Ovulate cones are described as Cordaitanthus shanxiensis S.-J. Wang and J. Hilton sp. nov.; each cone contains several cardiocarpalean ovules that have a distinctive tuberculate integumentary structure and are assignable to the morphospecies Cardiocarpus tuberculatus S.-J. Wang, J. Hilton, and B. Tian. The reconstructed plant most closely resembles C. dumusum from the Late Pennsylvanian of North America, but (often subtle) diagnostic characters are well distributed across the organs of the two conceptual whole plants, permitting confident distinction at species level. The plant is reconstructed as a large, suberect or fully erect shrub.