Asclepias tuberosa it is, indeed. I know it as butterfly weed, too. I have a plant which self-seeded in one of my beds. Handsome plant.

Is regular milkweed also endangered in some areas? I treasure mine and get a thrill every time I see monarchs on it. I also have a large patch of vernonia fasciculata, aka ironweed, out back. Butterflies seem to go apeshit over that too.