Ah, the lengths to which I have gone in order to write a post entitled “Frogfruit”.
This, er, eccentrically-named plant is also called capeweed, matchweed, and turkey tangle fogfruit, probably not by the same people. It is described as “interesting foliage” by the Florida Native Plant Society.
The flower has a spherical purple center (a “drum head“), with a circle of small purple or white flowers ranged around it. The plant itself is a very hardy, adaptable, low-growing ground cover, with thin stems and green, toothed, oval leaves, which sometimes appears as a lawn weed. It is found throughout the southern half of the US, the Caribbean, Mexico, Central and South America.