Brassavola digbyana => Rhyncholaelia digbyana
 

That digbyana was moved from Brassavola to Rhycholaelia is well known. When I look it up, I can see that this was based on a taxonomic paper dated 1918. However, it was clearly not acceoted at that time.

Does anyone know when this change was considered official?

May 2007

http://www.platinumcoastorchidsociet...ctober2007.pdf

There's no mechanism for accepting name changes. Somebody publishes their opinion (which is really all that taxonomy is.) If others agree with it they start using it. If they don't agree they don't use it, and people forget about the name change.

It isn't accurate to say that taxonomy is an opinion. Any newly published scientific name, combination or transfer is an hypothesis. Evidence that supports the hypothesis must be presented. An opinion doesn't need to present evidence and isn't taxonomy (science). An hypothesis may or may not come to be widely accepted, and that should depend on the evidence, not opinion. New evidence or a new interpretation of evidence may change or invalidate the hypothesis at any time.

For naming of orchid hybrids, which is in the realm of horticulture (not taxonomy/science), names are official whenever RHS says they are. That is their prerogative as the recognized registration authority. RHS did make changes based on the source in Orchidtinkerer's link, but some of those weren't in place for long, such as placing Brazilian "Laelias" in Sophronitis. But I believe that May 2007 is correct as the time that RHS officially recognized Rhyncholaelia for hybrid registration (horticulture, not science).

Actually, Kew says they accepted the name change in 2003: Rhyncholaelia digbyana (Lindl.) Schltr. | Plants of the World Online | Kew Science

Acceptance by one institution, even one as venerable as Royal Botanical Gardens / Kew isn't "official" (as the original question asked). It's just one (influential) assessment of the published scientific evidence. The only sense in which Rhyncholaelia can be "official" is for the horticultural issues under the purview of the Royal Horticultural Society.

Actually, Kew maintains the monocot checklist so it is the end all be all for plant taxonomy. Kew is also run by the Royal Botanical Gardens.

---------- Post added at 01:58 PM ---------- Previous post was at 12:30 PM ----------

I should also mention RHS is for orchid hybrid registry, but is not involved with species nomenclature.

There is no "end all be all" for any science, certainly not taxonomy. At most, there can be "perhaps the most influential opinion, for the moment".

And I cited RHS only for "horticultural issues under their purview", but in that capacity RHS does have control of species nomenclature as it pertains to hybrid registration records.

I hate to be a stickler for this, but some organism groups have dedicated organizations that determine the official name and validity of taxonomic updates. This is true for plants and that organization is the Kew monocot checklist. If they don't accept it, then the name is not valid.

I agree. Look what happened to Pluto. Even had to be deleted from all the new books and documents etc.