Hemlock (Conium maculatum) is a poisonous biennialherb of the family Umbelliferae. It is a tall, erect, branching biennial, with a smooth, shining, hollow stem usually marked with purple spots. It has elegant, much divided leaves which when bruised emit a nauseous odour. The flowers are white in compound umbels of ten or more rays surrounded by a general involucre of three to seven leaflets. Research Hemlock