Oncidium/Rossioglossum identification

[kamoji]

I’ve had this gorgeous, almost purely yellow oncidium for around 10 years. I got it from an orchid show in the Bay Area, and it moved with me to the East Coast. What started as a medium-sized plant has grown so much over the years that I’ve split it into around 8 more medium-sized plants, some of which I’ve given away to friends. It produces the most amazing spray of flowers 1-3 times per year. Multiple plants synchronize their flowerings, so I get TONS of these flowers at the same time.

I’d like to finally ID it! The flowers look very similar to Oncidium Gower Ramsey “Pure Yellow”. Meanwhile, PictureThis is quite convinced that it’s Rossioglossum ampliatum (the “turtle shell orchid”), but all the photos I see online of this have more red coloring than mine.

Any ideas? Is it one, or the other, or something else? Thanks!!

[Roberta]

First, Welcome!

It doesn't look like any of the Rossioglossums I'm familiar with, which have bigger flowers that are more Odotontoglossum-like. (The name changes drive me nuts... they may all be Oncidiums now but...) As for which Oncidium? I don't think you're going to get an ID. There are pure yellow species, you cite a hybrid that also has a pure yellow form. So I think that the closest you'll come is "Oncidium" ...

[estación seca]

Pseudobulbs are very different between Oncidium/Rossioglossum ampliatum and Gower Ramsey type hybrids. Look up photos of pseudobulbs.