Toxicodendron
Hi KP - it was an old ref (one I added before wiki was asking for reference citation, or I'd have said where!), so may well be superseeded. Unfortunately I've mislaid where I got it from and couldn't find it again just now. If it doesn't match modern research, please do delete it. An awful lot of books do still keep it merged in Rhus though (particularly the Asian species like R./T. verniciflua), so I think the Toxicodendron species should also be linked from the Rhus page as a lot of people might look for them there. -