Here's the color that earned the specific name of roseus. It is the most common and natural of the many color varieties. This species is the source of two cancer drugs. Madagascar and its people have not benefitted from the medical and commercial use of this plant. It is a frequently used example of biopiracy. This plant contains poisons, but the substances involved are not easily digested, so it is not particularly dangerous.
Madagascar periwinkle will soon be available at your local nursury. It is much grown as a garden annual throughout the temperate zone. In the tropics it is a shrub and is seen just about everywhere, with human help or not.
My random list seems to be generating a lot of aliens lately. The solution to that would be more requests. Please! Relieve me of responsibility!