This is supposed to be a Michaelmas daisy, but Wikipedia informs me that the Michaelmas is part of the aster genus, which by decree is now found only in Eurasia: "After morphologic and molecular research on the genus during the 1990s, it was decided that the North American species are better treated in a series of other related genera."
So . . . maybe it's an African daisy? I don't know. The good folks of Louisiana don't seem to have kept up with their taxonomy and mostly still call this a Michaelmas daisy. And why not? Who cares what a bunch of egghead botanists think, anyway?
It looks like New England aster (Symphyotrichum novae-angliae). "Michaelmas daisy" doesn't refer to any particular species; it's just a generic term for any of the gazillion species of asters and aster-adjacents.
What we called New England aster was the metallic dark colored one that grew along the highways.
The term "daisy" started out as a metaphor for "day's eye" -- that is, the sun.
"Who cares what a bunch of egghead botanists think, anyway?" - Hey! I resemble that! 🙂
Symphyotrichum - Aster