I've not seen marigolds with this particular symptom of Aster Yellows, but Echinaceae does it fairly often.

I looked up crested marigolds, too, and it looks like the word "crested" has a different meaning in marigolds than it does in other plants I'm familiar with. Fasciated might be more accurate, like a cockscomb. That's actually what this bloom looks like, a tiny cocksomb.

You know, it might be a mutation induced by something other than the Aster Yellows phytoplasma! I just jumped on that because it can be common to a wide variety of plants.

With AYD, a plant can look just fine one day, but the next new bud on that plant might be mutated. As the disease works its way through the phloem system of the plant, unstoppable, the plant can soon become barely recognizable. It is transmitted from plant to plant by an innocent looking leafhopper.

I sure hope that you'll keep this plant so you can watch what happens. Let us know so we can be included in on the experiment!

ken

It looks to me like an experiment gone bad not any variety of marigold. Seed companies are always trying to develop and hybridize new varieties of flowers and occasionally one of these gets into a package of seeds.

I once years ago got a petunia from my package of seeds that was plain ugly. It had a huge flower about 5 inches across and a large throat and the flower laid semi open and it was mottled. I figured it was an experiment gone wrong and 1 seed got in my package. I suppose I should have contacted the seed company but I didn't. I just pulled it out and replanted a regular petunia.