Differences in "Sisters"
 

I bought a Stuartiana x self from Hauserman's a few years ago. I forgot about it and ordered another one. They are both blooming, notice the difference in color. The original is on the right.

Wow. That is remarkable!

How recently did you acquire the “new” one? Was it already in bud?

I think your first stuartiana is what you would expect from that species. The second is a var. nobilis which is known for being yellow.
Perhaps it says that on the tag?

Judi

I purchased it last spring 2020. Maybe even early fall. No, it was not in bud. You can't see the whole plant in the photo but, it's a tiny thing. It's in a 3" pot. So, obviously they are not the same cross but. They are quite different.

Well, Judi, you made me dig for that one (literally, that tag was buried.) So, you've explained the difference. Too bad for WW, I was going to send her one. 😉

I do think that those are two distinct varieties of the species... Agree that the first is the "typical" form, the second (yellow) is var nobilis. So I think that maybe two different plants were selfed... definitely worth having both!
Out of curiosity, does the typical one have mottled green foliage, the yellow one maybe with few markings on the leaves, with more reddish leaves? Those would be characteristics too.

They both look very similar

Congratulations for the blooms anyway!

Nobilis or not, your stuartiana are much more impressive than mine.

Is either fragrant?