Cicuta virosa (Northern water hemlock) is of the genus Cicuta. Other members of this genus include: Cicuta maculata (spotted water hemlock) and Cicuta douglasii (western water hemlock). All of these members are also known as Cowbane or water hemlock. This is a genus of extremely toxic plants in the family Apiaceae.

Water hemlock is a perennial herb which grows up to 7 feet tall. Stems are smooth, branching, swollen at the base, purple-striped or mottled (C. malculata only), and hollow except for partitions at the junction of the root and stem. An oily, yellow liquid oozes from cuts to the stems and roots. This liquid smells rank and resembles that of parsnips, carrots or mice. Leaves are alternate and toothed unlike the ferny, lacy leaves found in many other members of the Apiaceae family. The flowers are small, white and clustered in the umbrella shape so familiar to this family. The plant may be mistaken for parsnip due to its clusters of white tuberous roots.

The yellow resin contains cicutoxin , which disrupts the workings of the central nervous system. In humans, cicutoxin rapidly produces the following symptoms: nausea, emesis and abdominal pain, typically within 60 minutes of ingestion. This can lead to tremors and seizures. A single bite of the root (which has the highest concentration of cicutoxin) can be sufficient to cause death. In animals the toxic dose and the lethal dose are nearly the same. 1 gram of water hemlock per kilogram of weight will kill a sheep and 230 grams is sufficient to kill a horse. Due to the rapid onset of symptoms, treatment is not usually successful.

Water hemlock plants grow in sloughs, wet meadows, along streambanks and other wet and marshy areas. The genus is common throughout the North Temperate Zone with Cicuta virosa being most common in Europe and Cicuta maculata being most common in North America.

History

There has been some dispute whether it was a hemlock of the Cicuta genus or the Conium genus which was used in ancient Greece as state poison. This poison was adminstered as a method of capital punishment and certainly the Greek philosopher Socrates drank a cup of some kind of hemlock infusion at his execution in 399 BC. See poison hemlock for more information.

The typical dose, however, was not always immediately fatal. Sometimes it was necessary to administer a second cup of the poison.

...having drunk all the Hemlock juice, the quantity was found insufficient and the executioner refused to prepare more unless he was paid 12 drachmas.

--from an account of the execution of Phocian

Considering the toxicity of Water Hemlock this may be a case of misidentification.

See also

• poison hemlock

External links

• Ancient Poisons