Archaeopteris macilenta is distinguished from other species of the genus by leaves which are divided into narrow segments at their tips.

Archaeopteris macilenta leaves and fertile shoots are attached to wood which when permineralized is called Callixylon newberryi.

[3] Fossilized remains of the Archaeopteris macilenta were initially discovered in 1958 the continental beds from the upper Devonian in eastern New York and have since been located in other floodplain localities from the Catskill Delta.

[4] Despite being a fern with sporangia, the Archaeopteris resembled modern conifers and has been found to grow similarly with woody strength built in rings to support weight and height, protective bark that shields the xylem, and extra wood at the base of the branch to prevent breakage.

[6] Carluccio, Hueber, and Banks (1966) concluded, on the basis of internal structure, that the laminar appendages of the 'fronds' were helically arranged.