Commonly known as either deer fern or hard fern, Struthiopteris spicant is native to northwestern North America, northeastern Asia, and temperate Europe.
It is, however, not commonly known by this scientific name. Most resources online and in print will use Blechnum spicant. However, a 2016 paper by Gasper et al., Molecular phylogeny of the fern family Blechnaceae (Polypodiales) with a revised genus-level treatment, asserts this should no longer be the case. To summarize the changes, the authors published an additional paper, A classification for Blechnaceae (Polypodiales: Polypodiopsida): New genera, resurrected names, and combinations where they state in the abstract:
The fern family Blechnaceae, with about 250 species, has traditionally comprised one large genus, Blechnum, plus seven to nine smaller genera, most with fewer than 10 species. Several phylogenetic analyses strongly suggest that Blechnum in the traditional sense is not a monophyletic group. We propose a new classification for the family, with three subfamilies and 24 genera.
Or, perhaps a more approachable (and open-access) summary of the changes is available courtesy of the British Pteridological Society: A New Classification of Blechnum. Interestingly, the author of that article states, “Our native Hard Fern (Blechnum spicant) becomes Struthiopteris spicant a name that was well known in the past”. It seems like a case of what’s old has become new again; first named by Linnaeus as Osmunda spicant in 1753, Friedrich Weiss renamed it to Struthiopteris spicant in 1770. It would be another 2.5 decades before there was a suggestion that this entity belonged in Blechnum. I interpret the words of the author of the BPS article to mean that Struthiopteris spicant was a name used for many years, until it fell out of favour to Blechnum spicant.
Within Struthiopteris (according to the paper above),
…species related to this clade [group] have compact erect stems, with clustered frond rosettes at stem apices. Stems also produce long-creeping rhizomes that grow and form new rosettes. Other morphological characteristics include having strongly dimorphic fronds (but with occasional reversion in S. spicant to the monomorphic condition), pinnatifid sterile blades having many pairs of gradually reduced proximal pinnae
This contrasts with the core Blechnum, which typically have monomorphic fronds. If you are confused by the monomorphic / dimorphic distinction, see the second photograph; the upright fronds are reproductive and distinct from the basal vegetative fronds (and thus dimorphic, or two forms). True species of Blechnum will (typically) only have one physically distinct frond that is responsible for all of the photosynthesis and spore production.
Struthiopteris spicant is an excellent garden plant for temperate shade or woodland gardens. It is recognized as both a Great Plant Pick for our local bioregion and a UK RHS Award of Garden Merit plant for UK gardens. I associate it as a trailside plant along some of my favourite British Columbian rainforest ambles, so I have a particular fondness for it (it also helps that it is perhaps the easiest fern to identify locally when the reproductive fronds are present).
Interesting, this suggests that all the common Blechnums in Australia except B. penna-marina are now something else 🙂
More reading needed!
Looks like Blechnum penna-marina is now Austroblechnum penna-marina, from what I noted in the articles!
New to me too! Another change of labels… Thanks for all that info!
Thank you for the update
I’m fond of this fern, too – the upright reproductive fronds are beautiful with the others spread around them, often, as you note, on the side of paths in our area. If I understand correctly, the name change is based on studying/thinking about morphological differences?
The name change to an older name is based on a molecular assessment of a wide range of species within the family. What they found was that some species like the old Blechnum spicant were more closely-related to other species within the family than to the fern species that was first assigned the name Blechnum, Blechnum occidentale (the type specimen).
According to the rules of taxonomy, you then have a couple choices: 1) you can recognize fewer genera (so that Struthiopteris spicant could stay within Blechnum), but then you have to rename a bunch of other fern species to from whatever genera they are in (the ones in-between Blechnum spicant and Blechnum occidentale in terms of evolutionary relationships) into Blechnum. Or, 2) you can split up Blechnum (and perhaps other genera) into smaller groups with their closest relatives clustered in a way that can be justified morphologically.
If option 1 (and only looking at the character of monomorphic or dimorphic fronds), you’d have to say Blechnum can have either monomorphic or dimorphic fronds. If option 2, you can confidently say Struthiopteris nearly always has dimorphic fronds while Blechnum has typically monomorphic fronds. There would also be additional characters that would sometimes distinguish, sometimes overlap, but when you look at a set of 2, or 3, or 4 of them, you could confidently identify one or the other.
Thanks Daniel! I’m feeling like I would need to go back to school to get it sorted out in my head. But it does make sense. I respect the difficulty of dealing with new knowledge, naming, etc. – there’s a lot to consider.
One of my favorite ferns seen in abundance from living in the PNW (and seeing other species in NewZealand and Chile) before moving to Ithaca, NY. While I cannot grow this fern here at Cornell Botanic Gardens, I appreciate the update on the nomenclature and link to the British Pteridological Society site.