Are robusta and arabica the only bean varieties? On this site, and virtually everywhere, I hear people speaking about coffee in terms of "arabica" or "robusta". I know these are two coffee varieties, but are there others as well? Why aren't those as popular? Where can they be found?
Coffea Arabica and Coffea Canephora are the only two species of plants whose beans we use to make coffee - Arabica and Robusta respectively. 

However, you may have heard of other 'types' of coffee that might be confusing. For example Peaberry Coffee is not actually a separate bean type. 5-10% of harvested coffee berries contain only one bean (instead of two). These are usually discarded, but sometimes are collected and sold separately. They are normally Arabica beans.

Furthermore, since 2008, 9 new species of coffee plant have been discovered. These are not currently cultivated for beans though, as far as I can tell (though some species contain traits which would be desirable1 - self-pollination and caffeine-free beans).



1. Desirable for some people...