We locally, have called these" Queen Anne's Lace". When I googled" Queen Anne's Lace", the pictures were close, but showed some differences. I wonder if it is only a different time in the plants maturation. Either way I found it interesting looking at the little globes in the center of the little flowerets. Tom ( photo / image / picture from Calomaar's Garden ) ( photo / image / picture from Calomaar's Garden )
Here in Ohio what we call Queens Ann Lace is actually the lacey top of he wild carrot. And it dosen't look anything like your pics.
Sure does look like Yarrow, one at the end of it's blooming cycle. http://en.wikipedia.org/wiki/File:AutumnYarrow.JPG
I also think it is yarrow, here are two pics of two Queens that I have taken to compare it with. The Queen. ( photo / image / picture from Kildale's Garden ) Queen Ann's lace. ( photo / image / picture from Kildale's Garden )
Kildale's second pic of the Queen is what we call Queen Anne's Lace around here. It grows wild and is considered invasive, the garden centers aren't supposed to sell it even... I love it. I think it is very pretty. Figures, right? Calomaar, your flower is really neat looking, the yarrow.
I planted yarrow years ago - and it took over! I ended up pulling more up than what I left growing. It seeds too readily.