Two compression specimens of a narrow pteridosperm stem with transverse sclerotic plates in the cortex are described from the upper Namurian B (Upper Carboniferous) of Hagen-Vorhalle (Germany). The pattern formed on the stem by the cortical transverse sclerotic plates permits assignment of the specimens to the mariopterids, genus Karinopteris or Mariopteris. Elongate clusters of densely spaced, up to 40 cm long shoot-borne roots with first- and second-order lateral roots extend from one side of the stem. Based on comparisons with modern angiosperms, the pteridosperm's shoot-borne roots are considered with regard to their significance as adaptations to special physiological and mechanical requirements of scrambling/climbing plants. They may have (a) compensated for the stem's narrow xylem area by providing additional connections with the ground, perhaps in order to maintain sufficient water and nutrient supply, (b) formed a loose interaction with support plants, and/or (c) contributed to the formation and condensation of thickets by intertwining with parts of neighboring individuals.