WordNet (r) 3.0 (2006):

California fern
    n 1: large branching biennial herb native to Eurasia and Africa
         and adventive in North America having large fernlike leaves
         and white flowers; usually found in damp habitats; all
         parts extremely poisonous [syn: hemlock, poison
         hemlock, poison parsley, California fern, Nebraska
         fern, winter fern, Conium maculatum]