if you're ok with making it a ssp that would be easy to do

Ok I made a deviation that allows us to keep C. albiflorus
as a species https://www.inaturalist.org/taxon_framework_relationships/220493

I would like to return to the problem of Crocus vernus vs Crocus albiflorus. It's not a matter of subspecies or not. Crocus vernus was typified in 2013 by L. Peruzzi & al. on the basis of Swiss material: "Lectotypification of the name Crocus sativus var. vernus L. (Iridaceae) and its consequences within Crocus ser. Verni". Taxon 62 (5), October 2013: 1037–1040 (https://www.researchgate.net/publication/255710298_Lectotypification_of_the_name_Crocus_sativus_var_Vernus_L_Iridaceae_and_its_consequences_within_Crocus_ser_Verni). As a consequence of this "Crocus vernus (L.) Hill should correctly be applied to the plants previously known as C. vernus subsp. albiflorus (Kit.) Ces. (≡ C. albiflorus Kit.). The next available name for the species to which the name C. vernus subsp. vernus has been misapplied is C. neapolitanus (Ker Gawl.) Loisel.". This concept has been accepted by POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:436446-1) and by the most recent Italian floras and checklists (S.Pignatti, "Flora d'Italia", 2017-2019; Bartolucci & al., "An updated checklist of the vascular flora native to Italy" Plant Biosystems, February 2018, 152(2):179-303). On iNaturalist, all three binomials are currently available: C. vernus, C. albiflorus and C. neapolitanus, which is not correct: either we follow Peruzzi and POWO (best choice IMO) and synonymize C. albiflorus with C. vernus, or the old taxonomy, but in this case we must synonymize C. neapolitanus with C. vernus.

I am not sure if I understand you and the publication correctly.

It looks to me like the plants that were previously called Crocus albiflorus should actually be called C. vernus and all the plants that were previously called C. vernus should now be called C. neapolitanus.

If this is correct, there is no way we can merge the two taxa, since the publication does not doubt that they are 2 different species (or subspecies).

Not sure if we should do that based on this publication. What I don't understand here is how you can take a name that was used for one species and just assign it to another species. That would create a huge confusion, because no one would know which species is meant by that name?
For me, this would be a typical case of "nomen ambiguum". So the name "Crocus vernus" should no longer be used at all.
I don't think that this taxon change, even if it might be correct, would be helpful for iNat.

There is an other publication (in German) https://www.researchgate.net/publication/336363001_BEITRAGE_ZUR_BIOSYSTEMATIK_DER_CROCUS_VERNUS_-GRUPPE

Hello @alberto_colatore
For me, such discussions are always about learning and not necessarily about being right. That's why I'm digging a little deeper.

The term "nomen ambiguum" is defined in the wiktionary as "A name which has lost the ability to clearly identify a species because it has regularly been used by different authors to identify different species."
I would say that this is exactly the case here. Regardless of whether the name would now have the correct use.

In general, my opinion on changes in iNat is the following:
What use is it if the nomenclature in iNat is up to date with the latest scientific findings, if the observations behind the names do not match the names at some point, because the users have not yet received this latest information?
I think what is important to remember about taxon changes is that iNat is not a taxonomic database. iNat is primarily a collection of observations and the taxonomic framework should serve the cause of structuring the observations in a meaningful way. A taxonomic database, when new research is available, can simply change the name, give species status to a subspecies, assign a species to another genus, etc. . iNat, however, has first and foremost observations, not just names. In my opinion, too little account is sometimes taken of this fact.

You're right, there's quite a mess with the crocuses.

Again, so that I understand you correctly? What you technically want to do is a taxon split after only the Crocus vernus observed in the range of Crocus neapolitanus are called Crocus neapolitanus and the others keep their name. Then Crocus vernus and Crocus albiflorus are merged under the name Crocus vernus?

Please excuse my persistence.
If we do it the way you suggest, we would be mixing observations that have so far been called Crocus vernus and are almost certainly not Crocus vernus in the new sense, with observations (so far Crocus albiflorus) that are to a good extent actually Crocus vernus in the new sense.

I don't like that very much.

Thought:
Wouldn't it be more correct to form a Crocus vernus complex in which all the species you listed are included? Then we would make a taxon split for Crocus vernus without giving the species an atlas? Consequently, all Crocus vernus would automatically be assigned to the complex. Then one could merge Crocus albiflorus and Crocus vernus under the name Crocus vernus (s. str.).
@loarie is this possible and allowed?

@loarie
The complex would contain the species that alberto_colatore quoted from a publication:
"For the taxon traditionally known as C. vernus, it was suggested (D. Harpke & al., "Phylogeny, karyotype evolution and taxonomy of Crocus ser. Verni (Iridaceae)", Plant Systematics and Evolution, Jan 2015, 301 (1): 309-325) that it should be split in five species: C. heuffelianus, C. neapolitanus, C. neglectus, C. siculus and C. vernus (=C. albiflorus)."

Taxonsplit created: https://www.inaturalist.org/taxon_changes/108411
I have never done a taxon split before and would like to have it checked before I commit it.
The intention is to replace all observations named Crocus vernus with the complex Corcus vernus.

Then all Crocus albiflorus could be replaced by Crocus vernus (s.str.). We would then follow POWO again.

@loarie
@alberto_colatore
@kai_schablewski