You can use iNaturalist to explore but also join and start to create your own list of identified species. And it has terrific mapping features to show you where species occur.

So why do you need this site to help you recognize poison ivy, poison oak, and poison sumac?

Lots of reasons. 

First of all, anyone who spends time outdoors should be able to spot these plants right away. 

You need to know what to look for before you start to use iNaturalist: you can’t ID every single plant you come across.

And children, starting very young, should also learn to identify these plants.

So use this website for free, buy ID items if you like from the store, and use iNaturalist or other plant ID apps, but it really pays to know what these very difficult plants look like before it’s too late.