The architecture of Pseudosporochnus nodosus Leclercq et Banks:: A Middle Devonian cladoxylopsid from Belgium

New observations on trunks of Pseudosporochnus nodosus Leclercq et Banks (Cladoxylopsida) from the Middle Devonian (upper Eifelian) of Goe, Belgium, show for the first time the presence of significant contiguous scars on their surfaces. The morphology of these scars corresponds to the morphology of the bases of first-order, digitately divided branches characteristic of the genus. We therefore reconstruct Pseudosporochnus with a sturdy trunk bearing densely and acutely inserted lateral branches capable of abscission at their base. We reject previous interpretations of Pseudosporochnus that do not include lateral branching of the trunk. In proposing an architectural model for Pseudosporochnus, we believe it to apply to other mainly Middle Devonian plants that we place in Pseudosporochnales, Calamophyton Krausel et Weyland, Lorophyton Fairon-Demaret et Li, and Wattieza Stockmans. The largest trunks bearing branch scars that we can now positively identify as Pseudosporochnus from Goe' have a diameter of 13 cm and indicate a moderately sized tree.