No, the flower/seed heads are not bunched together like in your photos. I did have some odd fern type leaves show up in a few places around my dill, and the fern leaves look a bit like what you have below the flower heads. It may be some kind of bird seed, like thistle. Dill seed heads are not bunched like in your photos, and the blossoms are very tiny and seperate from each other as are the seeds that form afterwards. The seeds swell up and are green at first, then dry and turn lght brown. If you don't know what dill seeds look like, they are mostly flat ovals and have a darker bump in the middle. Seeds are only about an 1/8 inch long.

If it has a smell of dill, it could be some kind of hybrid.

"Dill seed heads are not bunched like in your photos, and the blossoms are very tiny and seperate from each other as are the seeds that form afterwards."

that is what I thought, but I also thought perhaps it was too immature to separate. I never grew dill.

Check out the pix at the link below. They are quite different from your photos.

Here is a link that might be useful: dill flowers

It could be Queen Anne's Lace, a relative of carrot and dill

The root of a VERY YOUNG Queen Anne's lace is edible (it is the original parent plant of the carrot) but it quickly becomes woody and unpalatable. Our current carrots are a very domesticated version of Queen Anne's lace

I now believe it to be a crop of carrots grown for seed.