Poison Hemlock (Conium Maculatum)

    Poison hemlock, also called conium maculatum, deadly hemlock, poison parsley, spotted hemlock, European hemlock, and California or Nebraska fern, is a poisonous plant with white flowers that grow in small, upright clusters. Each of those flowers then develops into a green, deeply ridged fruit, containing many seeds. After maturity, the fruit turns grayish brown. This plant starts growing in the early spring and usually grows for 2 years, however, in favorable locations, it may live longer. It grows along fence lines, in irrigation ditches, and other moist environments. It is typically 2 to 3 meters tall (6.5 to 10 feet) and has a hollow stem peppered with reddish or purple spots. Ancient Greeks used poison hemlock to execute criminals and political prisoners; one famous example is the execution of Socrates. 

All parts of the poison hemlock are poisonous, and the leaves are especially poisonous in the spring and up to the time the plant flowers. Even the dead canes remain toxic for up to 3 years. The main harm from eating the plant but it’s also toxic to the skin and respiratory system. This plant is acutely toxic to people and animals with symptoms occurring 20 minutes to 3 hours after ingestion. Symptoms for humans include dilation of the pupils, dizziness, trembling, heartbeat slowing, paralysis of the central nervous system, muscle paralysis, and death due to respiratory failure. Symptoms for animals include nervous trembling, salivation, lack of coordination, pupil dilation, rapid weak pulse, respiratory paralysis, coma, and sometimes death. For both people and animals, quick treatment can reverse the harm. 

Sources: kingcounty.gov, ars.usda.gov, my.clevelandclinic.org