Cowpen Daisy

Quarter sized flowers seems abnormally small. They can get 2" wide. Was it growing in shade? Helenium amarum has grass-like leaves.

Helenium amarum, Bitter Sneezeweed.

Verbesina enceliodes, Cowpen Daisy, with Asclepias fascicularis

To me, the leaves & buds on the Cowpen Daisy don't look the same as the OP.

The OP's plant is Verbesina encelioides subsp. exauriculata, hence the smaller flowers and other differences.

One interesting thing about Verbesina Ive recently discovered is that leaf arrangment is practically useless in identifying them. Several species can have either alternate or opposite foliage.

This is Verbesina alternifolia, with opposite foliage. You need to ID them by the phyllaries. If going by the foliage alone, this would appear to be Verbesina occidentalis.