This appeared as undergrowth in a pot of clematis a friend gave me about two weeks ago. Other things appeared in that pot too, but this little yellow one is something I'm not sure about. It grows in clumps, has a sort of woody stalk, and grows from runners. The blooms are tiny, about the size of the tip of a pencil eraser. It has no scent. The clumps are small and compact, as it blooms the stalk grows taller, but it's only about 6 inches tall even then.
I thought it was a Wallflower at first, but I'm not sure. Someone else suggested Crown of Thorns.
It's something I've known in the past, but is only vaguely familiar to me now. I hate when I forget things like this.
