I was just reading up on cashews (because of the OOT nuts thread). I found out the cashew plant is in the poison ivy/sumac family!!!
I then read a little more and also discovered that mangos are in the same family! That the rash causing urushiol oil from poison ivy is also in the roots, bark, leaves and outside skin of the fruit of the mango plant!!!! It is NOT in the fruit itself.
Way to crush my joy with buying 50 cent mangos from Walmart.