Try posting it in the "Name that Plant" forum. They know every plant in the universe over there.

Looks like a Calibrachoa

Wallflower?

One of the South African Acanthaceae tribe, Barleria repens from summer rainfall areas of coastal South Africa. Not completely frost hardy here in the SF Bay Area, but I've had this do well for about 5 years in a warmer west facing spot up against the house in Piedmont. It can bloom nearly all year in a warm sunny spot, but will also still bloom in dappled sun, and will climb into supporting shrubs if allowed.

I don't think it's Barleria. they have more prominent stamens.

I guess the jury is still out, then. I thought it might be just Stock. All of the plants on the little round table this plant is on were grown from collected seeds or were dug up as volunteers.
So I don't know where I got it or what it is, yet.
I do like it!