Purple thistle (aka yellow thistle) (Cirsium horridulum) is an annual or biennial herbaceous plant that occurs throughout Florida and in much of the eastern seaboard. This is a plant of roadsides and other disturbed habitats, and thrives across a wide variety of soil types in full to partly sunny conditions. It is a robust, wickedly spined plant. The caterpillars of the little metalmark butterfly are uniquely adapted to feed on it. This tiny, but beautiful butterfly, is featured in the photo nectaring on an aster flower. A husky flower stalk arises from the center of the rosette by summer. It, too, is spiny and eventually reaches a height of about 3-4 feet. Large spiny flower heads form at the end of each stem - and along a few side stems near the top. These open to large and very showy lavender flowers that are exceptional nectar sources for all types of pollinators. Though few wildflowers are better nectar sources, purple thistle is often there to stay once in the landscape--producing new plants from underground suckers and from the fluffy seed that gets carried everywhere by the wind. It is a hub of activity if you are out looking for butterflies, bees, and the like. You never know what you might see nectaring from it.