This article is poorly written, and the numbers are nowhere near correct. The amount of caffeine in an ounce of espresso, for example, is not even measured in grams, but in milligrams (thousandths of a gram). There are about 80 milligrams of caffeine in a shot of espresso and roughly 100-130 in a 5-ounce cup of coffee.

Caffeine is found not in 60 plants, but over 100 different plants.

This is only the beginning of what is wrong with this article. I will not bother to correct the rest of it.