An early Permian permineralized gymnospermous fossil stem is described from the Taiyuan Formation in Yangquan City, North China. It is composed of pith, primary and secondary xylems. The pith is hetergenous and septate. The perimedullary zone of the pith consists of parenchymatous cells with crowding pits. The primary xylem is endarch. Radial tracheidal walls of the primary xylem have annular, spiral and scalariform thickenings. The leaf trace is mesarch, diverging from pith margin as single or double bundles. The secondary xylem is pycnoxylic. It is characterized by mixed radial tracheidal pits, parenchymatous rays, various types of cross-field pitting, and axial parenchyma. The percentage of abietinean pitting on radial walls of current stem is 26%, and the araucarian pitting accounts for 74%. Scalariform tracheids are present adjacent to the tracheids of the primary xylem. Rays close to the pith are bi- to triseriate. In the mature part of the wood, rays are commonly uniseriate, 1-26 cells high. There are five types of cross-field pitting in the wood of current stem. The first type has 2-6 simple, horizontally broad elliptical pits in each field close to the pith. The second type is phyllocladoid, composed of 1-2 large pits with pointed tips in each field. The third type is pinoid, with 3-8 irregularly distributed in the field. Taxodioid-type cross-field pitting is the fourth type, and occasionally present. The last type is cupressoid, with 1-2 narrowly bordered pitsThe discovery of current fossil stem adds our knowledge to the diversity of arborescent gymnosperms during the early Permian.

permineralized stem, gymnosperm, cross field, phyllocladoid, Taiyuan Formation