Not all cherries are created equal. The Acerola cherry is grown in south Texas, but the majority of the crop is grown in the Caribbean and Central America, so it's not really a cherry to compare to the Montmorency cherry.
The Montmorency is grown in Michigan, New York, Utah and Washington and it has the most amount of Melatonin in it. It greatly aids in sleep and helps to relieve gout and Arthritis pain.
If you want a high source of Melantion, get the tart cherry powder, according to the book Tart Cherry Health Report, the tart cherry powder has 137ng of melatonin, while the cherry juice only 100ng. So get the tart cherry powder.
You can download a free copy of the Tart Cherry Health Report from Traverse Bay Farms. Here is a link http://www.traversebayfarms.com
if you are interested.