Pretty poison

Poison Ivy flowers
Toxicodendron radicans
I like the former Latin name Rhus toxicodendron better, because there was always the possibility of referring to urushiol - the oil in Poison Ivy that makes you itch - as Rhus juice.*
This FDA site on Poison Ivy isn't bad, but it should really emphasize the fact that many suburban yards are full of Poison Ivy roots, as my sister rediscovers every spring. Poison Ivy: not just in the woods!
Plus, the more you are exposed to it, the more sensitized you seem to become. (Soon my poor sister will break out just thinking about the plant.)
And any site on Poison Ivy should point out that you should never, ever, ever burn it. Tiny urushiol oil droplets are carried in the smoke, and as much as you don't want that smoke blanketing your skin, you really don't want it slithering into your lungs.
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*Most people use that term for the "lemonade" made from Staghorn Sumac, I know, but it's not nearly as funny.