Butterflies and a Mystery Flower

We continue to get assorted butterflies stopping in the garden, sometimes staying still for long enough that I can get a picture.

I've spotted the Eastern Tiger Swallowtail several times over the spring and summer, but this time it sat for a minute on the Milkweed for me.

This tiny creature is one of the several species of Hairstreaks that we can see, all with tiny 'tails' on the hind wings, those tiny protrusions on the lower left.  This one is a Striped Hairstreak, identifiable by the blue-gray spot capped with reddish orange.

This is a Fritillary, probably the Great Spangled Fritillary, though it's hard to tell without a good look at the open wings.  It only stopped for a few seconds, and I was lucky to be there with my macro lens and get 3 quick shots like this one, cropped about as much as I can afford to, before it fluttered off.

And this is my mystery flower.  It came up among other 'weeds' in the sandy soil on top of our septic bed.  It's only about one foot tall or less, and only about 1-1.5 inches across.  I simply can't find a match in my wildflower guide.  Neither the large yellow centre buttons and short yellow rays, nor the leaves (below), match anything I can find.

These are the leaves.  It's a bit like a Tansy, or a Ragwort, but these leaves are truly tiny, only about an inch long each, and there appear to be no different basal leaves which many meadow wildflowers have.  Can anyone help?

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