Pioneer Valley Fern Society

An Unusual Polypody Fern

Cut-leaved Polypody still growing & healthy

Since I have been highlighting some unusual forms or variations on our common native ferns this season, I thought I would provide an update on this pretty little fern as well. Back in June 2021 I found this highly dissected form of the Common (or Rock) Polypody (Polypodium virginianum) while out hiking in Shutesbury with some friends. After I showed it to Randy we tried to figure out whether it was a new species of polypody, or some kind of hybrid or variety. We were hoping to be able to name it Polypodium virginianum var. shutesburianum! When our local fern friends and experts were not familiar with this fern either, Randy contacted the fern expert Robin Moran, who was so very gracious as to reply to our email with information on this fern form. He told us it was not a new species or variant, just an unusual form of the Rock Polypody. He had seen it only twice before, in the southern US. I have been visiting this location several times a year since, to see how they are doing. They seem to be nice and green and healthy, and even have a few small new locations nearby.

When I was searching through postings of less common ferns in our area in iNaturalist this past week, I found two postings for this same fern, one in New Hampshire and one in central MA. How exciting! It was new to these 2 botanists as well. One thing I have been looking for each year is any presence of fertile fronds in this nice patch of the cut-leaved polypody. I have not seen any so far, yet there are clearly 7 little populations of them across a rock face, several feet to yards away from the large patch. There are approximately 60-80 fronds in the main patch. It is rather hard to count them since they are growing so close together.

If you are interested in seeing a photo of a frond of this cut-leaved Rock Polypody next to a frond of the common Rock Polypody (there is a nice patch right next to this unusual one), scroll back through these PVFS news articles to July 14, 2021. That news article has a side by side photo. If you ever happen to see another patch of this unusual polypody form, please let us know, we would love to see it as well!