madnep(n = noun.plant) wild parsnip - biennial weed in Europe and America having large pinnate leaves and yellow flowers and a bitter and somewhat poisonous root; the ancestor of cultivated parsnip;
The masterwort (Peucedanum Ostruthium), a tall and coarse European umbelliferous plant. [1913 Webster]
A biennial weed in Europe and America having large pinnate leaves and yellow flowers and a bitter and somewhat poisonous root; the ancestor of cultivated parsnip; called also wild parsnip. [WordNet 1.5]