Pleopeltis polypodioides should probably be split into a new taxon P. polypodioides (sensu stricto) and P. michauxiana, but unfortunately fern taxonomy on iNaturalist--and elsewhere--is a bit of a mess.

iNaturalist generally defers to Plants of the World Online (POWO, plantsoftheworldonline.org) for accepted vascular plant taxonomy. But the important caveats with the current policy include ignoring genera that start with the letter P, as well as ferns. So we're at a standstill at this moment.

(Also, if the iNat community disagrees with POWO, we can flag the taxon, have a conversation about it, and consider an explicit deviation from POWO on a case-by-case basis. In some cases the iNaturalist community has pointed out errors with POWO, which POWO will incorporate into their site in their next round of updates.)

You can read more about vascular plant taxonomic policy on iNaturalist at this journal post.

I've been doing it manually which is a little time consuming. I finished North and South Carolina.

From the curator guide:

Splits: When all of the output taxa have atlases we can automatically choose the right output taxon for a record with a location, e.g. if Observation 1 is in Belgium and Output Taxon A occurs in Belgium but Output Taxon B does not, we can just add new identifications of Output Taxon A to Observation 1. However...Where output atlases overlap, or if there's ambiguity due to output taxa without atlases, we fall back to adding identifications of the closest taxon that contains all of the output taxa, so if the input is Woofer and the outputs are Canis and Vulpes, all IDs of Woofer will be replaced with IDs of Canidae, b/c it contains all of the outputs and should be implied by all of the previous IDs. This is a little weird, we know, but it makes it easier for people to add new identifications to shift the community ID correctly. [more at that link]

Scott has this longer document that details more information about splits (page 18+).

Taxa:

[old] P. polypodioides sensu lato (#84022) - no atlas needed
[new] P. polypodioides sensu stricto (#782079) - Atlas
P. michauxiana (#698726) - Atlas

Steps:

"Rough consensus" that we're ok with Pleopeltis michauxiana being its own thing. I am.
Refine the 2 atlases linked above (more info on atlases here)
Draft the taxon split, maybe have someone review it for any issues
Commit the split
Review/transfer common names, synonyms, taxon photos, conservation statuses

Sounds like another can of worms.

It's probably not a big deal for us in practice. All the unsplit stuff at the moment is Mexican-Caribbean-Central American, where
a) we have relatively few observations, due to our observer demographics
b) we can rarely identify Pleopeltis down to species level anyway due to the diversity of species there and the lack of detail in photographs

So I'm OK with us treating the remainder of the P. polypodioides aggregate (less ecklonii & michauxiana) as a single species for now.

OK, I've done my best with the atlases, although the Caribbean range of the remaining P. polypodioides aggregate and limits within Mexico of P. michauxiana could use some work.

@monifern, do you know anything about this that isn't in the literature yet?