All "polyanthus primroses" in the database are filed under "Primula elatior subsp. elatior". I believe this is in error, due to the record in some taxonomical resources that considers "P. polyantha" a synonym of P. elatior subsp. elatior. However, polyanthus primroses are hybrids of mixed origin, not a subspecies. They should appropriately be filed under "Primula × polyantha", as a separate entity from the (much more rarely encountered) botanical species.

Primula x polyantha is listed as an accepted name in The Plant List, which is woefully obsolete and usually incorrect. GRIN and ITIS also list it as an accepted name, but their data date back to 2005 and 2011. The Catalogue of Life, last updated on 4/21/2015, recognizes Primula polyantha only as a synonym.

Primula x polyantha was supposed to have been a cross of P. veris x P. vulgaris, but many of the P. veris subtaxa are now synonyms for subspecies of P. elatior and P. acaulis, and Primula vulgaris and all of its subspecies are now synonyms for a variety of other Primula species, so the name of this hybrid taxon (P. x polyantha) is no longer valid.

If the polyanthus primrose cultivars in our database are known to be hybrids of mixed origin, they should not have a species listed at all, and should be identified as polyanthus primroses only by their common names.

It is my impression that the Catalogue of Life never lists "botanically" named hybrids. For example, you won't find "Helleborus x nigercors" there, but horticulturally, that's certainly what that plant goes by (and many of its cultivars are listed right here in the database). Just another example: Viburnum x bodnantense.
I don't think it's good practice to rely on the Catalogue of Life for names of non-naturally ocurring hybrids.
Similarly, horticulturally the polyanthus primroses are generally referred to as Primula x polyantha. In the absence of a better taxon, I suggest they be listed here under that name. Certainly putting them in P. elatior just because P. polyantha (without the "x") is listed as a possible synonym for that species is incorrect.

I'm not sure why you wrote this: "I don't think it's good practice to rely on the Catalogue of Life for names of non-naturally ocurring hybrids." Non-naturally occurring hybrids are never listed in our database.

Hybrid taxa (the names with an "x" in them) are naturally occurring hybrids. The CoL does include the names of naturally occurring hybrids, but only if they are accepted botanical names. In contrast to some other databases, including ours, the CoL doesn't include the x, but if you scroll down on this page for Cistus nigrescens, you'll see the words "hybrid taxon." That's how we know the "x" should be included in the name for our database.

http://www.catalogueoflife.org...

The name Helleborus x nigercors should not appear in our database because it is not an accepted name. It was supposed to be H. niger x H. argutifolius, but H. argutifolius is now merely a synonym, so the hybrid taxon name is no longer valid. I'm not sure what happened to Viburnum x bodnantense. It's V. farreri x V. grandiflorum, both of which are accepted names, but it isn't recognized as a hybrid taxon by the CoL, so perhaps it wasn't a naturally occurring hybrid.

You say: "...horticulturally the polyanthus primroses are generally referred to as Primula x polyantha. In the absence of a better taxon, I suggest they be listed here under that name."

Our database is based on the botanical names accepted by taxonomists. The name may be used horticulturally, but that isn't enough to warrant its inclusion. I will remove the P. elatior subsp. elatior from the cultivar entries because they now would be classified as hybrids of P. veris (or P. elatior) x P. acaulis, and there is no botanical name for that hybrid.

OK, I guess I'm not familiar with the deeper philosophies of the database here. I would have thought that horticulturally common hybrids such as H. x nigercors, which are a relatively distinct entity, deserve to be listed under that name (as they are currently), rather than put in a generic "hybrid" bin where they would sit next to completely different plants like Helleborus x hybridus (which is likewise currently listed in the database, but not represented in CoL). Is it the goal to eventually remove all references to such horticultural hybrids from the database?

The "deeper philosophies" simply require the use of currently accepted and valid botanical names. This does entail the eventual removal of invalid names. There are some outdated names in the database because taxonomic changes occur so frequently that it's difficult to keep up with them, but we do our best to update listings as the changes occur. In most cases, the common name of a plant preserves differences that may no longer be recognized by taxonomists. You'll find all of the polyantha primroses in our database, for example, if you search for Primula polyanthus.

The problem with "horticulturally common" names is that, in the world of horticulture, they can (and do) make up pseudo-scientific names for within genus crosses at a whim. It's generally better to just list the genus and the cultivar name rather than indulge an activity that's really little more than a marketing gimmick.

I agree, in general. But I would think that it would serve the gardening community better to maintain a way to keep distinct hybrid groups, such as Helleborus x nigercors, together including an association with the well-established name, even if the botanists don't recognize it. However, it sounds like a decision has been made to have botanical purity trump horticultural conventions at all times. One that I understand, but don't necessarily agree with. But then, I'm a newby here.

Perhaps adding the well-accepted but incorrect name in the 'also sold as' section would suffice? That has certainly helped me find plants which have undergone name changes I was unaware of (or perhaps I've only known them as the well-accepted name), and I learn something as well even as I grumble (e.g., Autumn Joy sedum is really Herbstfreude - a name with too many consonants I have no clue how to pronounce!).