Question: what is the difference between arugula and wild arugula?
Answer: Arugula and wild arugula is the same species. Just that the "this-is-not-arugula" is quicker to grow, so we have this "false" arugula sold as arugula, and started to call the true arugula as wild arugula (which is not wild, it is cultivated and selected since long time).