The Collaborative International Dictionary
Chaerophyllum temulum
Cow parsley \Cow" pars`ley\ (kou` p?rs`l?). (Bot.) An umbelliferous plant of the genus Ch[ae]rophyllum ( Ch[ae]rophyllum temulum and Ch[ae]rophyllum sylvestre).
Wikipedia
Chaerophyllum temulum
Chaerophyllum temulum (syn. C. temulentum), rough chervil, is a species of flowering plant in the family Apiaceae. Unlike several other species in the genus, C. temulum is poisonous.