Ah...found it!! This was growing freely in the area we last visited in Charlotte county. At first they look like "just a weed" and then you notice the fine, frosty-colored down-covered leaves and stems -- the soft mauve clusters of blooms embedded in star shaped settings, their clusters rich with shadows of magenta. So easy to walk on by unless you stop to look, and so beautiful upon closer examination.
I will continue my search and see what medicinal uses this plant may have. There are different types of Camphorweed, also known as Marsh fleabanes and other names, and the different ones have different medicinal uses. At least one type is used interchangeably as an arnica substitute...is that exciting or what! Here are some at this site, though I don't know specifically what the properties of the Pluchea baccaris are. I need to confirm the ones I saw are exactly the Pluchea baccaris