Archaeopteridales †

Wood-bearing, spore-producing plants

The Archaeopteridales were a group of progymnosperms, meaning that they were spore-bearing plants that possessed a cambium with robust woody growth. This combination of traits is not found in any living plants, since all extant spore-bearing plants lack robust woody growth. The group is named after the taxon Archaeopteris, which is the earliest known woody tree found in the fossil record (Middle Devonian). This plant had fern-like foliage that bore sporangia on specialized fertile leaves, which is the form genus for Archaeopteris. For many years it was assumed that Archaeopteris was a fern, until the 1960s when Charles Beck was able to demonstrate that these fern-like leaves were actually connected to fossil wood known as Callixylon. From a distance, these plant probably appeared quite conifer-like, but upon closer inspection, the leaves would appear fern-like. These trees were a major component of the Late Devonian and Mississippian ecosystems, and may have played a role in the Late Devonian extinction event.

Ecology & Form

Stem

Leaves

Reproduction

Classification

Embryophytes

└Polysporangiophytes

  └Tracheophytes

    └Eutracheophytes

      └Euphyllophytes

        └Lignophytes

          └Progymnosperms †

            └Archaeopteridales †

Geologic Age

Above: Archaeopteris root system at the Cairo fossil forest site (Credit: Charles Ver Straeten)

Above: Archaeopteris root system at the Cairo fossil forest site (Image credit: Bill Stein)

Diversity

Actinopodium nathorstii † 

Actinoxylon banksii † 

Archaeopteris † 

Callixylon † 

Eddya sullivanensis † 

? Fuellingia gilkinetii 

? Langoxylon asterochlaenoideum †

Siderella † 

Svalbardia †