Hemlock growing next to cow parsley

This image shows two umbelliferous plants growing together. The one on the left Hemlock (Conium maculatum) with a Cow Parsley (Anthricus sylvestris) plant on the right. The leaves look similar although hemlock leaves have a slightly iridescent appearance. The difference in the main stem is very obvious. Hemlock has a smooth, hairless, pale green stem with red blotches. Cow parsley has a ridged stem that can be green to purple in colour.