Oenothera biennis possibly

Thanks - but that isn't it. I have the primrose in our yard and this looks quite striking-have never seen anything like it.
Gopal

A Silphium perhaps, maybe S. simpsonii or S. perfoliatum.

Joe

Thanks Joe, but that isn't it either. I will try to get a better shot of the flower head tomorrow. In the meantime, I would describe it as similar looking to Fritillaria imerialis with the petals turned upwards instead of pointing down. The flower is terminal rosettes of green leafy parts (sepals?) with the yellow petals arising in between these clusters. There is no distinct individual flower except for the above.
Gopal

The flower head is reminiscent of this flower

Here is a link that might be useful: {{gwi:325066}}