Magic Wand rubber shift boot. (Gear Stick Boot) The first Minis had a very simple gearchange, the lever exits the transmission directly through the floor. This requires a special boot to accommodate the curves in the floor and tunnel and being rubber it eventually cracks with age and flexing.

Replace it with the real thing to keep wet or dry road crud out of the car.

See 14A6861 for the metal surround to hold this gaiter in place.