iNat taxonomy question: why are so many species not matched to the genus they're listed under?

I see this a lot when I’m browsing through photos. For example, the photo page for Genus Hypoxylon contains all the Hypoxylons but also contains:
Acrostaphylus pulvereus
Nodulisporium atroviride
Nodulisporium cecidiogenes
Nodulisporium gregarium
Nodulisporium tabacinum

It looks like Acrostaphylus and Nodulisporium are both listed as synonyms for Hypoxylon, but shouldn’t all the species within it match the nomenclature? Or is there some reason for it?

The placements are correct for Nodulisporium.
The type species of Nodulisporium is N. ochraceum. That fungus is now known as Hypoxylon fragiforme. Therefore the genus Nodulisporium is a synonym of Hypoxylon. That is how iNat treats the genus and so there isn’t an active name Nodulisporium. However not all species described in Nodulisporium have validly published combinations in Hypoxylon, and probably won’t have in the near future. Therefore the only home for the orphaned binomials is under the the genus Hypoxylon. It looks strange but it works and there is no other option for orphaned names under ICN within the iNat system. Under ICZN the situation is different because new combinations are not a nomenclatural acts and can be created as required. I suspect the iNat nomenclature/taxonomy module was designed by those familiar with the ICZN situation, but not ICN.


It’s probably a mistake. When a curator uses a taxon swap to merge two genera, there’s a box they’re supposed to check that will automatically update the names of the species, but it looks like whoever did that forgot to check the box.

As I explained in my earlier post it is not a mistake. For genera treated under the International Code of Nomenclature for algae, fungi, and plants then ticking box, as you suggest, would potentially create combinations that are not validly published (noting that ‘valid’ means something different under ICN compared with ICZN). It is a fundamental difference between ICN and ICZN.
Article 41 (


Thanks for the clarification! I didn’t read your response carefully and I didn’t realize that the ICN differs from the ICZN in this way. I can understand why it might be desirable not to give species new combinations “by default”. In these cases, how are you supposed to refer to the species without new combinations? Do they keep their old generic names, even though the genus itself doesn’t technically exist anymore?

You can only refer to these orphans using a validly published name, even though the generic parent has been synonimised. The fact that they don’t have appropriate combinations should act as a warning that these taxa require revision and the name should be used with caution. In the fungi we have many tens of thousands of old names without a good modern interpretation. Many of the orphans fall into this category. They will remain ambiguous, probably forever, due to lack of type specimens, inadequate original descriptions etc. In addition, you cannot make assumptions about correct placement because in fungi modern phylogenetics tells us that morphology is very frequently misleading. These old ambiguous names are best forgotten. Unfortunately the iNat species dictionary has lots of these old names, presumably added simply because ‘they were missing’ or to support uncritical check-lists. They usually have no associated observations. They are unecessary baggage in my opinion.

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