Two coffee species dominate the global coffee market: Coffea arabica, which is generally preferred for its taste, and the more robust Coffea canephora (robusta). Both types are cultivated in the Western Ghats, but it is only arabica that is grown in the shade of native rainforest trees, where the slow maturation of the beans produces the rich and complex flavours of the best coffees.
Read more at: http://phys.org/news/2015-08-coffee_1.html#jCp