Java. It is, of course, found elsewhere. When it was brought to England the Victorians loved it for it fit right in with their bedding craze. Everyone wanted them in their large flower beds.
The coleus is a member of the mint family and, therefore, has a square stem.
It has been discovered that Mazatec Indians of southern Mexico consumed coleus for its mind-altering effects. To achieve this effect one must take 50 fresh, large leaves and chew them thoroughly and swallow them. Some have dried and smoked the leaves. Scientists have not yet researched the chemicals producing this effect and warn folks against doing this.
The root has been used to treat heart and lung diseases, intestinal spasms and insomnia.
Forskolin is a chemical that is responsible for these treatments as well as for the coleus-related folk medications used for over 3,000 years in India.
The writer suggests that we simply enjoy the variety of colors; that is effect enough for us.