An architectural analysis of Archaeopteris9 a fossil tree with pseudomonopodial and opportunistic adventitious growth

Currently recognized hierarchies of lateral organs in Archaeopteris are presented and phenomena that mediate organography and organotaxis in the taxon are discussed. It is demonstrated that Archaeopteris is totally lacking extant architectural analogues, and the methodology employed in the architectural analysis of such fossil plants is introduced. Proposed growth categories or phases for the Archaeopteris plant are presented and tested against evidence from a large silicified log of Callixylon, the trunk of Archaeopteris. An architectural model is put forward that encompasses such growth phaseS. Finally, the occurrence of reiterative, opportunistic growth in Archaeopteris is discussed.