When in California and again in Oregon I was shown poison oak. While there a friend accidently brushed against some (we were looking through scrub for an old cemetery to check for any roses!) She came out in a nasty rash but our other companion had a remedy in the car in readiness.
While we have poisonous snakes I am happy that at least we don't have the poison oak and ivy(those poor early explorers!) or Argentine ants down here in South Australia. The argentine ants are rotten litter beggers as I found out when I stood on a mound in New Orleans.
I came home with the blisters on my legs.