I would have posted this as a reply to my existing thread, but it locked itself as I was typing this, even though it shouldn’t have for another day.
Over the past few months I’ve been slowly working through every UK/Ireland identification marked as Rubus but with no identified taxon past the genus level, as to classify what plants are blackberries of some description (for future analysis by someone far more versed in identifying blackberry species than I am) and what are raspberries, salmonberries, Chinese brambles and so on. (Hopefully I’m doing this right and using the site correctly - if I’ve ended up making a complete mess please do set things right.)
One thing I noticed early on but never thought to question until now is that not only is “Rubus fruticosus” an accepted species name, but there are many observations using this, even at research grade level. I find this confusing as to my knowledge this species name is intended as an ambiguous placeholder, equivalent to the “European Blackberry Complex” taxon which is also accepted by the site. Is there an important difference here I’m missing? Would the nonexistence of this taxon on the site be undesirable due to a lack of research grade identifications of European blackberries, or something else entirely? There is a very good chance here that I’m misunderstanding something extremely fundamental about how taxonomy works as a relative newcomer, so do elaborate on why things are the way that they are here.
iNat is following POWO for Rubus fruticosus. so i guess you could look at the sources that POWO is using to define this as a species to understand what exactly they think it is.
i know that Rubus taxonomy is quite complex / messy. so even if this is what is accepted today, things may change tomorrow.
Rubus are similar to Taraxacum (dandelions) in that they have apomictic reproduction which causes a huge mess in trying to delineate species boundaries. Deciding things in either direction tends to cause controversy (there have been many long threads on the forum and taxon flags about dandelions for example).
This is the case with how POWO treats Taraxacum officinale (it’s a synonym with section Taraxacum). I’m not as familiar with Rubus taxonomy and don’t see a taxon flag on R. fruticosus discussing this question.
iNaturalist users are concentrated in North America which is probably why the discussions there focus on American taxonomy. I would be unsurprised to hear if European taxonomy and identification is still undiscussed and messy, and also that there could be conflicts between European and American taxonomy for the genus if implemented consistently with how botanists in the respective regions usually do things.
The species complex for R. fruticosus no longer exists and was merged with the section when the section was created as part of the creation of the broader infrageneric taxonomy for the genus.
Probably a flag on one of the relevant taxa would be the best place for further discussion.
(Edit: there is a flag on R. fruticosus with a conversation about the common name and indicating that the species should only be used for the sensu stricto definition of the species for identifications.)