Caffeine: Traditional Sources - Plants

Caffeine is the most used drug on the planet.. (see Wikipedia link for details).   This post is related to where, and how much,   caffeine is in plant sources. 

• Coffee -   The plants are called Coffea Arabica  and Coffea Canephora .   Cheaper, easier to cultivate,   robusta coffee comes from the Canephora varieties and has almost twice the caffeine of arabica.   Espresso blends contain significant amounts of robusta beans.  Concentrations of caffeine are usually quoted in percentage of dry bean weight.   Using 2% as an average -  one scoop of coffee (about 12 gm) would have  240 mg of caffeine.   The amount extracted from drip methods could be about half. 
•  Tea -  Camellia Sinensis .  The leaves contain an average of 3% caffeine by dry weight.  
• Maté -   Ilex paraguariensis   and Ilex Guayusa.  This South American plant has leaves which contain about 1% caffeine.
•  Guarana -  Paullinia cupana .  The seeds of this Amazonian climber contain about 2% caffeine.
•  Cola (Kola) -  Kola Nut  from Cola Acuminata . The nuts/fruits  contain about 2% caffeine.
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