Hybrid weeping willows: there is (probably) just one... but not on iNaturalist

See related thread: A Couple of Things People Should Know About Salix babylonica where several posters agreed that S. babylonica (the classic weeping willow) doesn’t occur in places that have cold winters, and in those places a willow that weeps must be a hybrid.

In that thread, it’s mentioned in passing that the hybrid found in North America is Salix xsepulcralis and that S. xpendulina is synonymous with S. xsepulcralis. But this merge of the two taxa is a very recent change: it comes from Belyaeva et al.'s comprehensive paper The application of scientific names to plants in cultivation: Salix vitellina L. and related taxa (Salicaceae) which was only published in 2018 and isn’t yet reflected in most of the authoritative online sources. Most of them follow the Flora of North America (section: Salix babylonica), authored by George W. Argus and published in 2010. ITIS cites this as their main authority for accepting both taxa as valid names. In my particular location, the major reference work is the Catalogue of the Vascular Flora of New York State by David Werier, from 2017, which follows suit. I don’t even know which botanists have accepted Belyaeva et al.'s conclusions, but at any rate Kew’s Plants of the World Online does.

Most to the point, the Wikipedia articles that iNaturalist uses as species descriptions haven’t been updated and don’t even mention the synonymy!

Well, it seems that someone’s been silently moving all identifications of S. xpendulina to S. xsepulcralis, but nowhere on iNaturalist, as far as I can find, is there any explicit statement of why to do so. The pages for both hybrids exist, with Wikipedia “About” sections, and there isn’t even a “misidentification” note in the “Similar Species” section.

Shouldn’t this be addressed?

I am not a curator, but perhaps a good place for this discussion would be a flag on one or the other taxa



Argus (author of the FNA treatment) accepted Belyaeva’s earlier work on taxonomy of this group. I’ve downloaded the newer paper and am trying to see what happened to the taxonomy, but it’s late for me so I’ll continue this tomorrow.

This group of willows is prone to hybridization, sometimes with hybrids, so the taxonomy isn’t simple.

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There are two Belyaeva et al. papers to worry about… 2018 and 2021.

The plants Argus calls Salix pendulina in the Flora of North America are, in Belyaeva et al. 2018, Salix pendulina f. pendulina. No change is proposed in Belyaeva et al. 2021 on this point.

The plants Argus calls Salix sepulcralis in the Flora of North America are, in Belyaeva et al. 2018, Salix pendulina f. salamonii. Belyaeva et al. 2021 corrects a nomenclatural error in Belyaeva et al. 2018, and these plants become Salix pendulina f. tristis.

On the face of it, Argus and Belyaeva et al. differ not in the number of taxa recognized nor necessarily in their circumscriptions, but in their rank. Argus calls them species, Belyaeva et al. forms.

Personally, I have no opinion on what rank is appropriate, on whether both taxa are found in North America nor, if there is only one, which one it might be. So far as I can tell, though, Belyaeva et al. 2021 is correct on the nomenclatural question relative to Belyaeva et al. 2018.

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Hi @lmtaylor, welcome to the iNat Forum! Please use flag space (links above) to discuss issues with specific taxa on iNat.