Fern, Interrupted – Learning to Identify Wetland Ferns at Swamp School

Sweet fern, not a true fern

Last week in the midst of meetings and deadlines, I slowed down long enough to learn how to identify northeastern wetland ferns. I participated in a Swamp School webinar and after the training, I earned a certificate. Since I’ve written about ferns a few times for my Strange Wetlands series, I thought I better check myself, before I made a fern faux pas. And as it happens, I was wrong about one plant: sweet fern (Comptonia peregrina)  is a member of the heath family, not a true fern.

The “Swamp Seminar” on wetland ferns started with the parts of a fern. Prior to this class, I knew to refer to the fern frond, which is the whole fern leaf, and I knew that rhizomes are the roots, but the rest of a fern’s morphology–well, that was new to me. It was fascinating to learn that a fern might be identified based on whether it is once, twice or thrice pinnate–meaning, the number of cuts on the pinna, or leaflet. Lady Fern, a common fern that grows in my “Fern Gully” at Nixie’s Vale, is three-times pinnate with a rough-edged leaflet, making it look lacy – the Victoria’s Secret brand of ferns. Other ferns have similarly feminine names like Venus Hair Fern (Adiantum capillus‐veneris) and Northern Maiden-Hair Fern (Adiantum pedatum), or Maiden-Hair Spleenwort (Asplenium trichomanes), which grows near waterfalls.  How lovely.

Northern Maiden-Hair Fern

For wetland professionals, the training also addressed whether each fern is an Obligate Wetland species, meaning that it always occurs in a wetland, also known as a hydrophyte (loves water); a Facultative Wetland species, which means that the fern usually shows up in a wetland, but can also be found in upland areas; or, thirdly, it may be a Facultative species, commonly occuring in both wetland and upland areas. Ferns that fit this last category–facultative, are still important to know because they may help someone identify the edge of a wetland. Identifying wetland plants is fairly complex. See this USDA page on wetland indicator information, if you are curious. If by any chance, you’re a real wetland plant enthusiast, I encourage you to check out this presentation on the newly revised national wetland plant list, which is run by the Army Corps of Engineers. 

National Wetland Plant List

Among the many types covered in the training, I learned how to identify Sensitive fern (Onoclea sensibilis), Fragile fern (Cystopteris fragilis) and Interrupted fern (Osmunda claytoniana), which I’m pretty sure I’ve spotted in Fern Gully. I have my notes to take into the field this spring when the fronds unfurl like fiddleheads and I can go on a fern ID scavenger hunt. The Swamp School webinar included access to an online tool kit, which allows me to reference handouts–and to get my certificate. I found the website and webinar training well-organized and jam-packed with knowledge and inspiration. I really enjoyed this class.

For those who are interested, Swamp School also offers classes on wetland delineation–in both classroom, field and webinar formats with live, interactive training. Marc Seelinger is the founder–and he’s a terrific instructor, too.  Right now he’s got a series of wetland delineation classes posted on the SwampSchool.org website, but there are also webinars and workshops on occasion. After all, inspiring minds want to know.