For Sunday's Opinion pages, artist Justin Renteria illustrated the above poison ivy girl. It accompanies an Op-Ed by Deborah Blum, the Pulitzer Prize-winning science writer and author of "The Poisoner's Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York," in which she defends and even praises poison ivy as a beautiful and environmentally essential plant. Read on to learn why.

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-- Alexandra Le Tellier