Polyantha rose (R. chinensis x R. multiflora, at times given the scientific designation R. x rehderiana) is not found in the plant database, and undoubtedly would not be allowed because it doesn't appear in the Catalogue of Life (The Plant List does include it). So where should information/photos about this hybrid (seed-grown, so no cultivar name) go?

We don't list hybrids without a cultivar name, and Rosa x rehderiana doesn't qualify as a hybrid taxon because it doesn't appear to occur naturally in the wild, so the only thing you can do is to post your photos on the generic Rosa page and include your information in the photo captions.

Which makes it non-searchable, right? It just doesn't seem right that a stable hybrid (comes true from seed) does not have a place in the database. Just because a plant doesn't occur naturally in the wild doesn't mean it doesn't exist, or can't be a worthy garden specimen. It still seems to me that some of the database policies, while appealing to a strictly scientific mindset (I'm a scientist, I understand) are not helpful to gardeners trying to find information. While I don't want to keep stirring things up, I do encourage some real consideration of this topic, rather than reiteration of a policy without discussion of its merits in these cases.

So if somebody is lucky enough to have a specimen of x Gordlinia grandiflora (Gordonia x Franklinia), where would they upload their pictures? It certainly isn't a naturally occurring hybrid, is not recognized by CoL, is "unresolved" as far as The Plant List is concerned - but it exists, and is a quite desirable plant to grow. Does it have a place in our database?

I can help you with the Gordlinia. We can and do list the intergeneric hybrids ("x" genera) after they are discovered and the research has been published.

http://garden.org/plants/brows...

Actually, some of these names don't last long because the ease with which two genera can be crossed is later explained by the lack of differences between the genera. XDigiplexis is one example. It was supposed to be a cross of Digitalis with Isoplexis, but all of the Isoplexis species turned out to be synonymous with Digitalis species. As a result, the plants were found to be Digitalis x Digitalis hybrids and no longer needed a special intergeneric name.

Inter-species crosses within genera are not included in our database, however, unless they occur naturally. They are included if they have cultivar names. One reason is that it would be a waste of time and resources to list every possible cross between the species of every genus. Another is that the names chosen for these crosses often are merchandising conveniences and have no basis in science.

Rosa x rehderiana is not listed on HelpMeFind.com, a database of more than 40,000 roses. It is not included in the major taxonomic databases, and GRIN even calls it an invalid name.

http://www.ars-grin.gov/cgi-bi...

Your information about the rose, however, would be searchable if you were to write an article for ATP about this rose or create a thread in the Rose Forum to give us your information about this rose.

Thanks for the information about gordlinia. It is not findable by searching the database for gordlinia. Would it be possible to have these intergeneric hybrids be findable by their "cross" name without the "X"? I don't think most gardeners consider the "X" to be part of the genus name.

Also, would it be possible to include hybrids of two species in the database by referring to their two parents, when the "named version" of the hybrid is not considered valid? On my PlantLinks site, I extended the use of subsp./var./forma subtaxons to also accommodate such cases, as exemplified on this page: http://www.robsplants.com/plan...

You were unable to find Gordlinia because I had just created those entries and it takes a while for them to be included in our search data. That's why I gave you the link to all of them. You will find it now, with or without the "x."

As for your other question, if you mean something like this entry on your site, then I have to say that we have never included entries of this type and probably never will. We don't list unnamed hybrids. We do list the accepted hybrid taxa.

http://www.robsplants.com/plan...

Ah, I didn't realize the gordlinia entry was new. Thanks for creating it. I wish I could populate it, but it's not reliably hardy here