and thankyou for the acorns
Yes, it is a seedling and I just went out to see what it was doing after our four inches of rain two days ago (welcome rain not damaging) - just a little soaked looking perhaps but still with slightly different individual florets;
I think it's just because they change as they mature and as there are several stages of maturity in each phlox flower head it looks like the heads started with different florets - make sense?
Nevertheless, the fact that the florets change that much as they mature makes this seedling quite special I think.