For some reason, I lost one of the pics. Refer to the one below before being befuddled by my OP.

They are both Solidago, just different species, there are many. If you want IDs, we would need the location, and close up pictures of leaves,(top and underside), stem, basal leaves, and flowers with involucres.

In your previous post https://www.houzz.com/discussions/6317517/anemic-looking-goldenrod-soil-vs-sun you said the seeds came from the same patch and put the differences down to growing conditions. Do you no longer think that’s the case?

I doubt they could be the same species, due to conditions. The leaf sizes are very different. I collected seeds for Oligoneuron rigidus and had a Solidago speciosa grow from those seeds. Most likely a speciosa seed flying through the air got caught by the Stiff Goldenrod seed head.

From the first picture I can barely make out the different flowers and I can’t distinguish any leaf size differences.

I just looked at the 1st picture. Solidago canadensis has a lot of variation. The 2 side by side, could possibly both be S. canadensis. Ive seen it look like both forms. They are both Solidago. The patch looks like what S. c. would do if left alone for a few years.

https://youtu.be/ZKHFk64FXOo

The followingpics might provide more information

The previous pics might provide more information.

They are of a cutting I made today about 1.5 meters

up from the ground, except the bee pic is from Sep. 12.

I think it's the same species.

I revisited this post to get the exact ID. This goldenrod species is Solidago altissima, or more precisely the Solidago altissima complex which includes 3 varieties. The different varieties can occur together, and there can be specimens that exhibit intermediate stages between varieties.

This photo shows Solidago altissima var. altissima on the left. The upper leaves are not reduced in size. The goldenrod on the right is Solidago altissima var. pluricephela. The inflorescence is elongated and the upper leaves are reduced in size.

In this photo the shorter plant on the left is Solidago altissima var. pluricephela. The plant on the right looks intermediate showing traits from both Solidago altissima var. altissima and Solidago altissima var. pluricephela.

You're welcome! I learned a few new things in the process, so thank you too.