Description of need:
Due to the acceptance in the International Code of Nomenclature for algae, fungi, and plants of publishing hierarchical infrataxon ranks and iNat having the rank hierarchy having all infrataxon ranks at the same level there are taxon leaves on iNat of validly published names that represent the same thing.
The example provided in the code (https://www.iapt-taxon.org/nomen/pages/main/art_24.html)
24.1. The name of an infraspecific taxon is a combination of the name of a species and an infraspecific epithet. A connecting term is used to denote the rank.
Ex.1.Saxifraga aizoon subf. surculosa Engl. & Irmsch. This taxon may also be referred to as Saxifraga aizoon var. aizoon subvar. brevifolia f. multicaulis subf. surculosa Engl. & Irmsch.; in this way a full classification of the subforma within the species is given, not only its name
This means that in increasing resolution all of following would be valid
S. aizoon ssp. aizoon
S. aizoon var. aizoon
S. aizoon subvar. aizoon
S. aizoon f. mutlicaulis
S. aizoon subf. surculosa
With iNats current ranks that means S. aizoon ssp. aizoon, S. aizoon var. aizoon, and S. aizoon f. multicaulis could all be on the site and placed at the same level. IDers either using keys that go to the different levels or even an IDers confidence in a key that breaks down the hierarchy could enter valid IDs at different levels. This would mean that the IDers are in disagreement when really they are talking about the same taxon at different levels of resolution.
Feature request details:
Change the rank hierarchy below species from subspecies=variety=forma to subspecies>variety>forma so where multiple levels exist they can be grafted to each other.
The code also talks about subvarieties and subformas which are not in iNat and I don’t know if they are used enough to necessitate adding but if added also should fit in a hierarchical method.
I understand the thought behind this request, but I think it would lead curators and users of the taxonomy down unproductive rabbitholes. Let me explain.
As correctly noted, in botanical nomenclature, the name of an infraspecific taxon is the name of a species plus an (one) infraspecific epithet, connected by a rank designation. These “trinomials” are the only things that are valid names for infraspecific taxa.
In the example, Saxifraga aizoon var. aizoon subvar. brevifolia f. multicaulis subf. surculosa correctly follows the sequence of ranks given in Article 4 of the Code when more than one rank is used. But it is a classification and not a name. The valid name, and therefore the valid taxon, is still only the trinomial, Saxifraga aizoon subf. surculosa, as Article 24.1 states. Therein lies my concern.
Unlike taxon names, taxon classifications are not governed by any rules beyond the sequence of ranks to be used, as long as the names used in the classification are each valid trinomial names at the rank used.
With valid trinomial names in hand, anyone can create any combinations and classifications of them that they like, without review or publication or support in any literature. Secondary sources like POWO do not track classifications, only names.
So the result could end up being a classification “free-for-all,” with infraspecific taxa being grafted and regrafted at any curator’s whim, and no authority against which to measure the results.
I think iNaturalist got it right when they kept all infraspecific ranks at the same level, because any given infraspecific name can only be a trinomial at one rank.
I am pretty sure that only one trinomial combination “Saxifraga aizoon aizoon” can be active on the site at one time. So if it was already present at subspecies rank, the system would not allow you to add the same combination at variety or subvariety rank. I think that is a consequence of having all of the infraspecific ranks at the same level.
But you are right that
and that the two could be in disagreement. Whether they should disagree or not depends entirely on the classification one is proposing to adopt.
I don’t know whether there is really a need to be able to graft infraspecific taxa to each other, but I support this to the extent that it would at least make the search filters in explore work the way that you would expect.
If I’m understanding your meaning here, ones expectation of how the filters would work would, again, depend entirely on whose classification (what goes under what in the hierarchy) one is expecting iNaturalist to adopt.
Some floristic treatments for a species put their infraspecific taxa in multi-level hierarchies, other competing ones just use a single infraspecific rank. Which one the site should adopt would be purely a matter of opinion, since multi-level classifications are not covered by our external taxonomic authorities. Whose opinion will we end up following?
To be clear I just mean that if I filter by hrank=variety&lrank=variety, I would expect to only get observations taxa ranked as variety, instead of all observations of any taxa ranked as any infraspecific rank, which is how it works now.
I’m not sure how I feel about this. At least in the treatments I’ve seen, it is pretty (extremely?) rare to have more than one infraspecific name. While there are some subspecies that have varieties, in most cases variety and subspecies are treated pretty much equally and it is just at the whim of a particular treatment author whether or not they prefer to use a subrank when they aren’t putting it between other ranks. Some would argue that having a subspecies without first having a variety is kind of silly as it is like having a subgenus without a species. While there is somewhat of a battle between those two ranks in the plant world, it seems like animal people just ignore everything below subspecies in the animal world. So, that means variety and subspecies are treated equally in most cases and certainly when comparing between plants and animals. Whether or not there is a good reason to use forma seems pretty debatable and I’ve never even heard of someone going to the extremes of subforma. You may have given some lumpers heart attacks by springing that on them.
Anyway from a logical standpoint, it makes sense to have each rank in its proper place. Maybe not from a practical standpoint of addressing the majority of taxa though. What about those plants where the same names just shift between variety and subspecies depending on the author that did the treatment? The fact that iNat mostly ignores infraspecific taxa already, I doubt that they would want to go into this much detail in their taxonomic structure. There are many requests hoping that iNat could be less species-focused and more minimum-ranked-taxa focused. Adding more lower levels into the iNat taxonomic structure might make it even less likely for those requests to ever happen.