Oxalis?

Me three! Does it have pink blooms? These make wonderful container plants. I love it!

Thanks, but I have a source of seeds. I'm not positive that they are the native, which I would prefer, but they are closer than St Paul, if I can time the visit right and only have to go out once. Just trying to get the approx. timing of seed ripening. I don't think this plant releases its seeds within two nanoseconds of ripening, as some plants do, but hangs on to them a little while.

Definitely Oxalis. I have these in my butterfly garden. (Accidentally) It transplanted with one of my liriope border plantings. At first, I wanted it gone completely, but later found that if you control the climbing onto other plants, it makes a beautiful "living mulch."