Horticultural hybrids and iNat

I’ve been noticing an issue that isn’t exactly a bug, but more a consequence of how iNat systems work that is causing less-than-optimal results, and I wanted to start a discussion about it.

As I’m sure most of you know, horticultural hybrids are difficult to properly place in a taxonomic tree. Many of them are bred from dozens of different ancestor species, and crossed and back-crossed so many times there’s nothing resembling a “species” left of them. Under the current systems, the only accurate ID they can be given is just to leave them at genus-level.

iNat also has the feature of automatically marking things as cultivated if a certain percentage of observations with that ID in that area are already marked cultivated.

Where this becomes an issue is in areas that have both a large number of plants marked “cultivated” at genus-level, and less-common native species in that same genus. Native plants uploaded with only a genus level ID then are automatically marked cultivated and disappear into the observation graveyard, never to resurface unless someone scrolls through thousands of garden photos to pick them out.

A good example is genus Rosa in Alameda County California.
This is a native Baldhip rose which has automatically been marked cultivated: https://www.inaturalist.org/observations/169521897
If someone adds a species-level ID the cultivated vote will vanish, but not many people want to scroll through 47 pages of casual observations to look for observations like this.

The potential options I can see here are:
1). Stop automatically marking genus-level observations cultivated if there are native species in that genus in the area. Downside: a lot more garden plants will be cluttering up the ID queue.

2). Create a “catch-all” ID that can be given to horticultural hybrids to move them out of genus-level and distinguish them from the ones that have a species but have merely not been identified to that level yet. This goes against iNat’s policy of not inventing taxonomy, though.

3). Enable a way to search for observations marked casual by the automatic system while filtering out the user-marked ones, to make it easier for identifiers to check.

Anyone else have other ideas for solutions?


Whoa - that’s not good. How about restricting the use of automatic Casual votes to the species level? I would think that would be easy enough to implement. The downside would be more genus-level observations left to be marked as Not Wild by identifiers, but I can live with that.


We have an open request to separate Casual / Cultivated / Not Wild
from Needs ID.
Then identifiers could choose better, and observers would be encouraged to say Not Wild up front, instead of waiting for IDs first.


I can’t live with that. That would be terrible, especially for things like roses and orchids


Do you have the link? I can’t find it… :cry:


While I am not personally opposed, I have read previous discussions frowning upon the intentional addition of horticultural hybrids. (Here it is) It’s a little bit confusing because we do currently have some in the system (a few that come to mind: Pelargonium × hybridum, Pelargonium × domesticum, Arctotis × hybrida, quite a lot of Leucospermum and Protea, × chitalpa tashkentensis, × chiranthomontodendron lenzii)

This seems like the most easily implemented and least controversial.




I agree. The flags section is already able to distinguish between user-added flags, and automatically added ones, so applying the same logic to DQA items would seem to be less disruptive to everything than the other two suggested options.


I think the biggest issue is there are just so many of them, and in a lot of cases the parentage isn’t even known. I believe the generally accepted rule at the moment is to only add naturally-occuring hybrids and the few horticultural ones that have become problematic invasives.

True, but where I do most of my IDs (New England in the US), there are both wild and cultivated roses and orchids (and rhododendrons and dogwoods and viburnums, etc.), so I guess I’m just used to marking things Not Wild?

1 Like

I think the solution is to just add the horticultural hybrids. Not sure why they are typically omitted. After all, they could escape, or the parent species could cross in the wild.

And this issue shows that the omission of horticultural hybrids adversely affects wild observations. Just add the horticultural hybrids already.

1 Like

found it : https://forum.inaturalist.org/t/what-to-do-with-artificial-hybrids/39873/2

I will edit my above post

1 Like

EDIT: Disregard this comment since I misunderstood, leaving it here for reference.

I was thinking about the system automatically marking obs as not wild as well. If I understand it correctly (please let me know if I missed the mark here), it would require two users to mark the obs as wild and “disagree” with this automatic vote before it would be eligible for RG again. I quite like the automatic vote system and see its benefits, but it seems to me that one user’s vote should outweigh the automatic iNat vote.

A solution to this might be to only count the automatic vote as half a vote, so it is still marked as “not wild” if there are no disagreements, but can also be undone easily by one “yes, wild” user vote. This wouldn’t resolve the whole issue of native genus-level getting lost in the casual pile right away, but at least it would make it easier to pull them out of there when you find them.

1 Like

a single vote for wild will balance out the not wild vote. So

is indeed what already happens


Thanks for clearing that up @thebeachcomber !


Some hybrid taxa are included on iNat, while a lot of others are not, and it gets confusing. In some of these cases, the hybrid taxon is defined as a very specific cross but then misapplied as ID to all sorts of others. Example: Rhododendron x hybridum exists as a taxon on iNat. There is very little info available on it but according to POWO it denotes specifically the rhododendron-azalea (‘rhodazeala’ or ‘azaleodendron’) hybrid R. maximum x R. viscosum. However, I see it used on iNat for all sorts of common garden rhodo varieties such as R. ponticum hybrids, the ‘Roseum’ Catawbiense hybrid series, R. indicum azalea hybrids etc. Technically, this ID should only be applied to R. maximum x R. viscosum per its definition/publication, for which I can’t even find any reliable pictures because all that pops up when searching for R. x hybridum online are others labeled with the same ID.


On the one hand, as a pedantic plant taxonomist, I should totally disapprove of misapplying the name of a horticultural hybrid to any but the exact cross it was intended to refer to. On the other hand, iNaturalist doesn’t focus on cultivated plants and the name is useful for labeling observations as, essentially, Cultivated Rhododendron or whatever. Do I don’t mind the misapplication in this context.

Opinions will differ.


I tried implementing a “general hybrids” taxon for Penstemons since there are so many horticultural ones with multiple parents. It got shot down because it’s not a real taxon. I think casual users get discouraged because marking their garden specimen as just “Penstemon” doesn’t feel like a good answer. It also makes it harder to distinguish between escaped (and therefore not cultivated) cultivars and wild species that have not yet been identified to species.

I don’t think adding a bunch of artificial hybrids is a good way to go because then it just encourages users to upload garden plants because they are rewarded with an exact identification.


I’ve run into this as well, having tried to clean up the roses section many times.

I can understand the need to have exact hybrids named, but with some, like garden roses, it quickly becomes a nightmare. There’s some people who’ve opted out of community taxon altogether after getting many replies about their rose not being Rosa chinesis, and I honestly wouldn’t even know how to distinguish one from a regular garden rose if it poked me in the face. All I can do is assume it’s not, because it’s usually not.

The advantage of having a catchall term on a case by case basis, if there’s one that can be applied, is maybe catching the many, many people who choose China Rose for their rose, rather than going with ‘Rosa’. However, I don’t know if going with something like a rough ‘Garden Rose Complex’ (excuse my mangling) would even work in taxon terms.


The issue you have raised is important. There are cases in which horticultural hybrids can be as invasive as their parent taxa like the hybrid Lantana L. “Callowiana”.

I have to disagree with this point. Here some examples of non-hybrid taxa:

  1. In Italian cities Pines (P. pinea among all) are very frequently cultivated. In the surroundings there can ben wild individuals. But almost all those growing inside the city perimeter are just cultivated. See, for example, Rome where - I do not know why - so many tourists feel the need to make an observation of the pines all growing in line and all almost of the same age (that means cultivated). Of course very few of them mark such observations as captive/cultivated and, to be honest, the automatic marking is doing great.
  2. Nerium oleander: it is extremely (even too much) cutivated as an ornamental in our cities. It can produce some offspring but the vast majority of observations from central-northern Italy refer to just cultivated plants. Again the automatic marking contributes to save time.

I am not sure if I got the point. If you meant to create a species in iNat taxonomy with the hybrid/cultivar name, I agree. One example: recently a Sparaxis has been found in Italy. It turned out to be a hybrid but there are no latin name available. So, the availability of “Sparaxis hybrida” could have been useful. The same happens for Narcissus and many others.

This could be useful.