NuMex Twilight
Numex Twilight's rainbow
Numex twilight is one of the most unusual varieties of chili pepper developed at New Mexico State University (which creates all "NuMex" breeds of plant). It grows about 18 inches tall, and becomes covered in peppers that start out purple, then move through yellow and orange, becoming red when fully ripe, producing a rainbow effect on the green plant.
The NuMex Twilight chilli has a Scoville rating of 30,000 - 50,000, or about as hot as a Cayenne pepper.
It is a hybrid based on the Thai Ornamental pepper.