I fell asleep after reading Amy Stewart's Wicked Plants: The Weed That Killed Lincoln's Mother & Other Botanical Atrocities and all night long my dreams were overwhelmed by Stewart's interesting shrubs, trees, flowers, etc.
*If you've ever wanted to know how to nix someone (with plants), make them hallucinate (with plants), or, just give them really bad diarrhea (with, you guessed it, plants) then I recommend reading this book.