From a series assembled and written by Alexis over the summer:
The prehistoric plant series continues today, and we progress through the geologic time scale to the Triassic period. Much thanks to Keith Board for sharing his photo of Osmunda claytoniana, which was taken in a swamp forest at the Indiana Dunes State Park in Porter County, Indiana. Keith is a contributor at this neat blog, Get Your Botany On!.
Osmunda is a genus of about six terrestrial fern species. Osmunda species grow in open, wet environments such as bogs, swamps, and lake edges. The genus has a wide distribution throughout the globe, though it is limited by climates that are too cold or dry (Tryon & Tryon’s Ferns and Allied Plants (1982)).
Osmunda claytoniana has the “oldest known fossil record of any living fern”, and can be traced back to the Triassic period. This species can also be considered a living fossil, because it appears almost identical to a fossil fern species from 200 million years ago, Osmunda claytoniites. It has gained the common name interrupted fern because of the appearance of its fronds, on which the brown fertile pinnae “interrupt” the green sterile pinnae.