The November issue of National Geographic had an article about a garden in England that contains some of the most poisonous plants in the world. A visitor cannot enter the garden without supervision.
Although not specifically mentioned in the article, I could not help but think of water hemlock (Cicuta maculata), a plant native to North Dakota.
You may recall that poison hemlock (Conium maculatum), is the plant that killed the Greek philosopher, Socrates. Water hemlock could also have done the job — all plant parts are toxic to humans and livestock. It is one of the deadliest plants native to North America, some say the deadliest.
Consuming a small piece may be fatal
The fleshy roots and lower stem are particularly toxic and plant parts are reportedly most toxic during spring. Consuming even a small piece of root or lower stem may prove fatal. An hour or so after ingesting the toxin (cicutoxin, a potent neurotoxin) symptoms such as abdominal pain, nausea and vomiting, convulsions, and seizures may occur, leading to a painful and miserable death. The toxin can also be absorbed in the skin.
Both poison hemlock and water hemlock are members of the parsley or carrot family (Apiaceae) which includes carrot, dill, and caraway. The family may be characterized by alternate, mainly compound leaves with white or yellow flower clusters in umbels which are flower clusters (inflorescence) with each flower stalk arising from the same point.
Location and appearance
Water hemlock ranges over most of the United States and Canada. It is quite common in North Dakota and, as the name implies, grows in wet places such as marshes, wet meadows, streambanks, springs, and the like. It grows to around 6 feet tall and produces large clusters of small white flowers around 4-6 inches across during July-September. The leaves are alternate and compound, with each division consisting of 3-7 rather narrow leaflets with toothed margins.
Poison hemlock
It should be noted that poison hemlock, which is not native to North America, has been documented in the state and is becoming naturalized. There are also a few non-toxic lookalikes. However, these species are difficult to distinguish.
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So, next summer if you see a tall plant with large clusters of small white flowers and compound leaves growing in wet areas, it is probably best to just let them be.
