The Peanut also called groundnut is  a legume crop grown mainly for its edible seeds.
It's interesting to think that a peanut is actually a legume- I always forget that. Have you ever had boiled peanuts? They are popular in the Southern us. 
Yes they are very tasty when salted. They are planted mostly in tropics and subtropics regions
I wonder why so many people have peanut allergies now?
In 2014 42 million tonnes  was planted
Wow those are some big numbers. What country is the biggest producer?
I'm not sure but what I know is that  peanut  belongs to the botanical family Fabaceae