@ddennism @gwynethgovers @tsn @evan8 @danavan can you get behind this proposal?

I'm in favor of all these changes, eventually. The introduction of subgenera won't be noticed by most users anyway. Subgenus Trillium will be useful, though, as a finer-level ID for its members in eastern North America that are difficult to ID to species. It'll be the "erectum complex" asked-for in another flag without the messiness of the question of that complex's strict monophyly considering the Asian and Western North American taxa in that group.

The only renaming at the level of the species binomial involves the two Trillidium species, which is probably going to frustrate and confuse a lot of people. Personally I wish they'd just have denoted Trillidium as a fifth subgenus of Trillium- after all, it's a monophyletic group sister to the rest of the genus in their trees and therefore would have been as valid a grouping at subgeneric rank. They just essentially say "eh, they're different enough morphologically plus divergence time, etc..." This is a problem for an international project like iNaturalist because the name Trillium govanianum is in wide use among researchers, particularly in Asia, who study that plant's bioactive compounds, use in folk medicine, and imperiled conservation.

I'd say we implement the subgenera exactly as Tom outlined, but wait for POWO to decide on the Trillidium question, in the meantime leaving those two species as direct children of genus Trillium. I just feel uncomfortable acting fast without some sort of input or buy-in from Asian researchers, especially for such an arbitrary change. But luckily weighing those types of international concerns is what POWO is all about, so I think we should just punt the question to them and follow their lead.

For simplicity, I spun off a separate flag to create three subgenera (and nothing more).

@trscavo - Yes, it would include the Sessilium to Sessilia change.

I guess I had just assumed that "Sessilium" was already in the same form as "Trillium" - a neuter, singular noun in the nominative case, and that Rafinesque intended to coin it as a novel noun, regardless of the fact that "sessilium" happens to also show up as one of the plural forms of the adjective sessilis. But whatever - Lampley et al. make a case that it ought to be an adjective here too, and that's a simpler (and therefore also better) interpretation. If it's a plural adjective, then it's Sessilia.

FYI, the content that's getting pulled in from Wikipedia for Sessilia says that it's "an unranked clade of barnacles." :)

The taxon swap has had an undesirable consequence. Just checking to make sure that that consequence is expected.

The taxon swap that implements the Sessilium-to-Sessilia name change has caused the Observation Taxon of some observations to change. In particular, if the most recent ID was subgenus Sessilium, and that ID was a disagreeing ID, the taxon swap causes the Observation Taxon to revert back to its previous value.

For example, observation 70914190 has had the following Observation Taxa (in chronological order):

Little Sweet Betsy (Trillium cuneatum)
Sessile-flowered Trilliums (Subgenus Sessilium)
Little Sweet Betsy (Trillium cuneatum)

The latter was a result of the taxon swap.

Is this an unfortunate consequence of the taxon swap? I assume so but I'm afraid now someone needs to review all similar observations and reissue a disagreeing ID.

https://forum.inaturalist.org/t/allow-taxon-curators-to-edit-taxon-names-reducing-pointless-taxon-changes-for-fixes-like-epithet-ending-changes-or-adding-hybrid-symbols/15050