Archaeopteridium KIDST., 1923

Fossil-genus Archaeopteridium KIDST., 1923

R e m a r k s. This fossil-genus has been reviewed by Rowe (1992), who pointed out that it differs from both Sphenopteris and Sphenopteridium in the absence of transverse markings on the rachis caused by cortical sclerotic plates. However, its distinction from Spathulopteris is less clear-cut. Kidston (1923) noted that the main difference is that Archaeopteridium pinnules tend to be decurrent and more broadly attached to the rachis, and have a more lobed margin, but whether these differences are sufficient to merit a generic separation is unclear. Nevertheless, for the time being Archaeopteridium has been kept as a separate fossil-genus.