Aneurophyton is also known from the Middle and Late Devonian. Aneurophyton is similar to Tetraxylopteris in overall form, but its branches are arranged helically rather than decussately. Fertile ultimate appendage showing recurved sporangia. In fertile axes, ultimate branches are replaced by dichotomies with multiple homosporous sporangia arising along the length of each fork of the branch. The main axis of Aneurophyton has a lobed protostele and produced a small amount of secondary xylem from meristematic regions between the lobes.
Known axes are relatively slender suggesting a bush or vine growth form rather than a large tree.
In fertile examples, a branch bearing stalked pairs of elliptical sporangia replace webbed leaves. Archaeopteris foliage showing webbed leaflets and fertile branches intermixed on the same axis. Woody stem is Callixylon. Webbed leaves and two-dimensional branching differentiate Archaeopteris and its relatives from related plants such as Aneurophyton and Tetraxylopteris . Heterospory is also derived in Archaeopteris .