Crassula is a huge genus, with most of the species native to southern Africa. A lot of them are miniatures, but Crassula perfoliata var. falcata is in the big side, and robust forms can grow to be several feet tall. It is from South Africa, and was long known simply as Crassula falcata, but it is now considered a variety of the variable C. perfoliata. It differs from other forms in its sickle-shaped leaves (falcata means sickle-shaped), and it is sometimes called the Airplane Plant or the Propeller Plant because of this distinctive shape.
I have a small plant of this. Let’s see if it survives