Water hemlock has small, white flowers that grow in umbrella like clusters. Side veins of the leaves lead to notches, not to tips at the outer margin. The thick rootstalk of water hemlock contains a number of small chambers. These hold a highly poisonous brown or straw-colored liquid that is released when the stem is broken or cut. Thick, fleshy tubers and slender individual roots grow from the bottom of the rootstalk.
Water hemlock grows in wet seepage areas of meadows, pastures, and in streams.
It reaches a height of 0.5 to 1.0 meters. The plant is a perennial in the carrot family. It has also been confused with wild parsnips, other herbs, and medicinal plants. In cases of water hemlock poisoning in humans, contact a poison control center and obtain emergency medical assistance as quickly as possible. Poisoning results in severe seizures and convulsions that must be controlled to preserve normal ventilation and cardiovascular function.