The Jerusalem artichoke (Helianthus tuberosus) is a root crop native to the USA and Canada, east of the Rockies.  It forms heavy yields of tubers that contain inulin, a carbohydrate that humans cannot break down.  This makes them lower in calories than potatoes, but also hard for some people to digest.  Many varieties exist, some improved through breeding, but more were probably taken directly from the wild.