Could anyone please ID this garden weed with pretty purple flowers? They sprung up in Argentina, where I live, at the beginning of summer. The chickweed in the same pot is unrelated, of course. Bigger plants have hairy stalks and rosette-like leaves that spread in a circle from the central stem.
I'm so sorry I took a while to answer, I had to go away unexpectedly.
Thank you so much for the identification, all of you! I have been wanting to know what this little beauty is forever. I am so happy and so grateful to have found this forum. A million thanks!