One of the well known hypotheses about plant domestication (Edgar Anderson) dealt with the idea that nomadic camps had dump heaps, places where inedible things got pitched. Reuse of camps would bring these people back after some time and discover that seeds had sprouted and grown leading to the idea and practice of purposefully growing things. Sure, maybe, but nomadic people probably already know how plants grow, but they see no need to plant what they can find in the wild reliably. While throwing apple peels on our own dump/compost heap this AM, TPP noticed a nice looking seedling emerging along the edge and an examination determined that it was a mango seedling from some discarded pit. Well, it will not grow here in the upper Midwest, and it is a member of the poison ivy family, so TPP will deal with the leaves carefully. Sure is a cutie though.