Cinnamon Fern & Interrupted Fern

Osmunda cinnamomea & Osmunda claytoniana
Thursday, June 17, 2010

Cinnamon Fern

The woods around Mountain Lake are filled with cinnamon ferns. These ferns are so named because of their long, cinnamon-colored fertile fronds bearing sori, which produce spores. Cinnamon ferns can grow up to 6 feet high, with fronds as wide as 1 foot. Their sterile fronds are composed of deeply lobed pinnae (the “leaflets”) with slightly pointed tips. No sori are ever present on the sterile fronds. Besides sexual reproduction, the ferns can also produce new shoots from their rhizomes. They are deciduous; in early spring, new, tightly curled fronds will emerge called fiddleheads, which grow into new sterile fronds (the “leaves”) and fertile fronds (the cinnamon “fruiting bodies”). They can be found in moist woodland, as well as near ditches, streambanks, or other damp areas. They inhabit the eastern and southeastern US and eastern Canada.

Interrupted Fern
Interrupted ferns are extremely similar to cinnamon ferns, with a few exceptions. The most obvious is that instead of separate fronds being sterile or fertile, brown, fertile pinnae “interrupt” leafy, green, sterile pinnae on a single frond. The result is a frond typical of the sterile fronds of a cinnamon fern, with, about midway up, a set of pinnae that are brown and covered in sori. One other distinguishing feature of the interrupted fern is its lobes, blunter and more rounded than the sharp ones of the cinnamon fern. Similar to the cinnamon fern, it is resident of moist woods, though present in habitats slightly drier than those typical of the cinnamon fern. It is found more rarely around Mountain Lake than the ever-present cinnamon fern. They can be found, in the appropriate habitats, in a large part of the eastern US and Canada.
The cinnamon fern was collected behind Clayton and the interrupted fern was collected near Burns.
Articles by Hazel Galloway