White rose campion!
Or, as my grandmother always called them, and therefore as I call them, "mullein pink."
I brought home a standard fuschia-colored one of these from the Billerica plant swap, and then kicked myself, because I realized as soon as I got home that the fuzzy things growing in the lawn were also these...and I'm not exactly overrun with space. Since I've only ever seen fuschia ones, I assumed I'd be getting fuschia again.
Well, the one from the plant swap was fuschia, as expected. The one rescued from the lawn has just started blooming, and it's a beautiful snow white. There were two others in the same lawn clump, but they seem to be in their first year, and won't be blooming this Summer. I assume they will also be white.
It's time to start examining the neighbor's yards more closely, to see if any of them are growing the white ones, which might have re-seeded. I don't recall seeing any. Otherwise, I wonder if they are a long-lost remnant of the former owner's garden, which is otherwise completely non-existent.