Spotted a weed this morning, so as a public service, here's how to spot a weed ...
Q: Did you plant it there?
A: No.
Answer: It's a weed!
Q: What are the odds it is not a weed and in fact a rare and special plant which has chosen your garden to grow in, because you, too, are rare and special?
A: One in about, roughly ... oh, let me see ... a billion, or thereabouts.