A few years ago I went to North Carolina to visit family and friends. When I came home, I brought back to France a tiny cutting — not more than three or four little round leaves on a stem — of a plant known commonly as a Donkey's Tail. It's a sedum — Sedum morganianum is the Latin name. It's from Mexico and is sometimes called Burro's Tail or Lamb's Tail.
Caution: I just read on another web page that the sap from this sedum's leaves can cause infections and even blindness if you get it in your eyes. I don't know if it's true but better safe than sorry.