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Water hemlock plant (spotted cowbane) – how to identify this poisonous plant and diagnose/treat poisoning.

Water hemlock plant tall stem and white flowers

About the Water hemlock plant

Water hemlock or spotted cowbane
Cicuta maculata
Parsley (Apiaceae) Family

How to identify the Water hemlock plant

The Water Hemlock, also known as spotted water hemlock, spotted parsley, spotted cowbane, and the suicide root, is a perennial herb in the carrot family.  It is very difficult to distinguish it from other, similar-looking plants.  Water Hemlock may grow to 1.8 meters (6 feet) high. The stem is smooth, hollow (solid when very young) and sectioned off like bamboo, and is often purple or red striped or mottled on mature plants.

Water hemlock plant Cowbane along river bank

Its 2–5-inch leaves are made up of several leaflets that are small, shiny, green, lance-shaped, and pointed with sharply toothed edges.  The lower leaves are large and long-stalked while the upper leaves are divided into three leaflets and each again divided into three (twice ternate).

Its flowers are small (no more than 1/8 inch across), have five petals, green or white, and grow in clusters that tend to form flat umbels giving them the appearance of white, rough-skinned umbrellas. Its whorls of slender, fibrous roots may have hollow air chambers and, when cut, may produce drops of yellow oil which turns reddish-brown when exposed to air.  Its cylindrical or oval-shaped fruit is dry, tan, or brown, only a few millimeters long, and ribbed on the outer surface.

Differentiating Water hemlock from Queen Anne’s lace or Wild parsnip

Water hemlock poisonous plant Cicuta virosa in the Oslo Botanical Garden, Oslo, Norway

Its appearance to water parsnips is similar. Water hemlock has a hollow stem that is often purple or red, while the stems of similar plants are usually solid. Additionally, water hemlock has clusters of white flowers that are arranged in an umbrella shape, while the flowers of similar plants are arranged differently. The primary difference is in the leaf structure.  Water parsnips have leaves that are only once compound while Water Hemlock has leaves that are three times compound.  Water hemlock also has a large swelling at the stem base which water parsnip lacks.  In addition, careful examination of a water parsnip leaf will show the vein running to the pointed end of the toothed edge whereas with Water Hemlock, the vein runs to the edge of the leaflet in between the toothed edges.  Also, the water hemlock has bracts at the end of each flower cluster whereas the water parsnip has bracts at both the base of the flowers and the main flower head.

Water hemlock is a highly poisonous plant that belongs to the carrot family. On the other hand, hemlock is a poisonous tree that belongs to the parsley family. Hemlock has a thick trunk and dark green needles that are arranged in a spiral pattern. The Water Hemlock may be distinguished from the true Hemlock as follows: (i) The pinnae of the leaves are larger and lance-shaped; (ii) the umbel of the flowers is denser and more compact; (iii) the stem is not spotted like the true Hemlock; (iv) the odor of the plant resembles that of parsley.

Where to find the Water hemlock plant

Water hemlock grows in wet or moist ground like swamps, wet meadows, stream banks, lakes, rivers, and ditches throughout the United States and Canada.  The plant is indigenous to both eastern and western parts of North America, and it is often found in ditches, marshes, meadows, pastures, and stream banks. The plant prefers acidic soil. Water hemlock can also be found growing in water.

Water hemlock plant poisoning

This plant is very poisonous and even a very small amount of this plant may cause death.  The toxin found in this plant is cicutoxin, which is most concentrated in the roots but can also be found in the flowers and seeds. Children have been poisoned simply by using the plant’s hollow stem as a whistle and people have been poisoned simply by rubbing the plant’s outer surface.   Its roots have been mistaken for parsnips. It is considered to be North America’s most toxic plant.  The majority of the poison is concentrated in its roots.

Symptoms of poisoning include nausea, vomiting, severe cramps, tremors, confusion, weakness, dizziness, drowsiness, hallucinations, delirium, tingling, numbness in the skin, dilated pupils, and violent and painful convulsions.  The results of these symptoms can cause brain swelling, muscle breakdown, and kidney failure.  It can cause death in as little as 15 minutes.  It also can cause long-term, permanent neurological damage.

How to treat Water hemlock poisoning

Treatment of water hemlock poisoning requires immediate medical attention and can involve a combination of different methods. In addition to anti-convulsant drugs, activated charcoal may be administered to slow toxic poisoning (if it is administered soon after ingestion).

Poisonous Water hemlock plant flower clusters

The first step in treating water hemlock poisoning is to seek emergency medical care. The individual should be taken to the nearest hospital or healthcare facility as soon as possible. It is important to note that time is of the essence when it comes to treating water hemlock poisoning, as the effects of the toxin can be fatal if not treated promptly. In some cases, even a small amount of the plant can be deadly.

Once the individual is under medical care, the healthcare provider will likely try to induce vomiting to remove any remaining plant material from the stomach. Activated charcoal may also be given to help absorb any remaining toxins in the stomach. This is because water hemlock is rapidly absorbed by the body, and it is important to remove as much of the toxin as possible before it can cause more damage.

In severe cases, the individual may require hospitalization and the administration of intravenous fluids to prevent dehydration and electrolyte imbalances. They may also require treatment with anticonvulsant medications to control seizures. This is because water hemlock poisoning can cause seizures, which can be life-threatening if not treated promptly.

It is important to note that there is no specific antidote for water hemlock poisoning. Treatment is mainly supportive and aimed at managing symptoms and preventing complications. This can include monitoring vital signs, providing oxygen therapy, and administering medications to control symptoms such as nausea and vomiting.

Famous cases of Water hemlock poisoning

There have been several famous cases of water hemlock poisoning throughout history, including:

The Lewis and Clark Expedition

During their exploration of the Western United States in 1805, Meriwether Lewis and William Clark and their team of explorers encountered water hemlock and mistakenly ate its roots, mistaking them for wild parsnips. Several members of the team suffered from violent seizures and convulsions, and one member died as a result of the poisoning.

The Death of Socrates

It has been speculated that Socrates, the famous Greek philosopher, died as a result of drinking a tea made from water hemlock. The accounts of his death suggest that he experienced convulsions and paralysis before ultimately passing away.

The Death of Livy’s Son

The Roman historian Livy wrote about the tragic death of his son, who mistakenly ate water hemlock while out foraging with his friends. The young boy suffered from violent convulsions and died within a few hours of ingesting the plant.

Water hemlock plant picture identification guide

  • Water hemlock plant in ditch along roadway
  • Water hemlock plant in ditch alongside a road
  • Poisonous Water hemlock plant in the wild
  • Water hemlock plant on bank of a pond
  • Water hemlock plant Cowbane along river bank
  • Water hemlock plant tall stem and white flowers
  • Poisonous Water hemlock plant Cicuta maculata leaves, in roadside ditch
  • Water hemlock plant Cicuta virosa
  • Water hemlock plant Cicuta virosa
  • Water hemlock plant closeup of seed buds before flowering
  • Water hemlock plant Cicuta maculata right before flowering
  • Water hemlock plant stem, leaves, and flowers
  • Poisonous Water hemlock plant flower clusters
  • Water hemlock plant Cicuta maculate in flower
  • Poisonous Water hemlock plant closeup of flowers
  • Water hemlock poisonous plant flowers closeup
  • Water hemlock plant clusters of white flowers
  • Water hemlock plant white and yellow flowers
  • Poisonous Water hemlock plant stems and young leaves
  • Water hemlock poisonous plant Cicuta virosa in the Oslo Botanical Garden, Oslo, Norway
  • Water hemlock plant leaf closeup
  • Water hemlock plant illustration artwork

Image Credits

In-Article Image Credits

Water hemlock plant Cicuta virosa via Wikimedia Commons by Kristian Peters with usage type - GNU Free. June 28, 2006
Poisonous Water hemlock plant flower clusters via Flickr by Joshua Mayer with usage type - Creative Commons License. September 3, 2016
Water hemlock plant Cicuta maculate in flower via Wikimedia Commons with usage type - Creative Commons License. July 9, 2012
Water hemlock plant stem, leaves, and flowers via Wikimedia Commons with usage type - Creative Commons License. February 8, 2021
Poisonous Water hemlock plant closeup of flowers via Flickr by USGS Bee Inventory and Monitoring Lab with usage type - Public Domain. February 12, 2019
Water hemlock poisonous plant flowers closeup via Flickr by USGS Bee Inventory and Monitoring Lab with usage type - Public Domain. October 18, 2019
Water hemlock plant clusters of white flowers via Wikimedia Commons by H. Zell with usage type - Creative Commons License. June 9, 2009
Water hemlock plant Cowbane along river bank via Wikimedia Commons by Anneli Salo with usage type - Creative Commons License. July 3, 2011
Water hemlock plant Cicuta maculata right before flowering via Wikimedia Commons by Laval University with usage type - Creative Commons License
Poisonous Water hemlock plant in the wild via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University
Water hemlock plant tall stem and white flowers via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University
Water hemlock plant in ditch along roadway via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University
Water hemlock plant in ditch alongside a road via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University
Water hemlock plant closeup of seed buds before flowering via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University
Poisonous Water hemlock plant Cicuta maculata leaves, in roadside ditch via Wikimedia Commons by Choees with usage type - Creative Commons License. June 24, 2012
Water hemlock plant Cicuta virosa via Wikimedia Commons by Meneerke Bloem with usage type - Creative Commons License. June 17, 2010
Water hemlock plant on bank of a pond via Wikimedia Commons by Krzysztof Ziarnek, Kenraiz with usage type - Creative Commons License. July 18, 2017
Water hemlock plant illustration artwork via Prof. Dr. Otto Wilhelm Thomé Flora von Deutschland, Österreich und der Schweiz 1885, Gera, Germany with usage type - Public Domain
Water hemlock plant white and yellow flowers via USDA by Robert H. Mohlenbrock with usage type - Public Domain. Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA NRCS. 1992
Poisonous Water hemlock plant stems and young leaves via Forestry Images with usage type - Creative Commons License. October 1, 2013
Water hemlock plant leaf closeup via Flickr by USGS Bee Inventory and Monitoring with usage type - Public Domain. August 22, 2019
Water hemlock poisonous plant Cicuta virosa in the Oslo Botanical Garden, Oslo, Norway via Wikimedia Commons with usage type - Public Domain. September 11, 2009

Featured Image Credit

Water hemlock plant tall stem and white flowers via Wikimedia Commons by Gilles Ayotte with usage type - Creative Commons License. Laval University

 

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