Interrupted Fern
Interrupted fern, Claytosmunda claytoniana, formerly Osmunda claytoniana, is found in many places in the Eastern United States and Midwest.
Osmunda claytoniana — iNaturalist map of O. claytoniana
Claytosmunda claytoniana — iNaturalist map of C. claytoniana
Interrupted Fern is one of the larger ferns in New England. It can grow as tall as 2 meters (6 feet).
Its distinguishing character is that the sori on the fertile fronds 'interrupt' the pinna about 1/3 up the rachis.
Without sori, can be confused with Cinnamon fern, Osmundastrum cinnamomeum.
Interrupted fern has a more open frond and the pinnules are more rounded.
Cinnamon fern has a woolly tuft on the underside of the pinna at the intersection of the rachis. Interrupted fern has no tuft.
Cinnamon fern will have left over woolly covering from its fiddlehead on the stipe. The interrupted fern stipe will be smooth and bare.
Large specimen. Weston, CT, USA
People's State Park, Barkhamsted, CT, USA
The sori emerging as the frond unfurls. Fairfield, CT, USA
Fiddle heads of C. claytoniana Fairfield, CT
The fiddlehead stage has the stipe lifting the crozier well above the ground before it starts to unfurl. Thus, there are not any pinna in the lower 1/4 or so of the blade.