Long-Lasting Morphologies Despite Evolution: Ferns (Monilophytes) Throughout the Phanerozoic

Successful evolutionary forms are characterized by their longevity in the fossil record. There are many plant groups that exhibit these traits; here we have selected the ferns as one acknowledged evolutionary model. Ferns are the most successful cryptogamic plants in geologic history and are known from nearly all fossil floras since their first appearance in the Devonian. Ferns, autotrophic organisms, have colonized nearly all types of continental environments over time [U1102]. Fern groups experienced rapid radiation at the familial level in the Carboniferous and are well documented in the fossil record thereafter. Their megaphyllous leaves are easy to recognize and have reproductive organs (sporangia filled by spores) borne on the lower side of pinnules. Although growth forms show great variability in morphology and size, all have retained this simple reproductive organization for over 400 million years from when first recognized in Devonian floras.