Wheaton, Illinois

As I was weeding the garden at my brother's house, I came across a couple of plants that made me stop and think. Were seeds put here intentionally or is this plant just a weed. Easy you think? Not really! I'm learning that plants grow at amazing speeds (even Sahara-like conditions couldn't stunt the grass here), and after a weekend - or four - the weeds really sprout up. So I need some help with the plant in the picture. Is it a weed or seed (i.e. planted)? Please help me! Write to mander10@gmail.com with advice.