Poison Hemlock, Water Hemlock, and Fool’s Parsley

Poison Hemlock (conium maculatum)
Poison Hemlock (conium maculatum)
Conium maculatum
Conium maculatum

Conium maculatum (poison hemlock) is a highly poisonous perennial introduced and naturalized in North America. Poison hemlock is infamous as the plant responsible for the poisoning of the philosopher Socrates after he was condemned to death for impiety in 399 BC. The toxin, coniine, is concentrated mostly in the root and seeds. About six to eight of the fresh leaves contain enough poison to cause respiratory paralysis, leading to death. However, death can be prevented by use of artificial ventilation until the toxin wears off 48-72 hours later, when spontaneous recovery typically occurs.

water hemlock3
Spotted Water Hemlock (Cicuta maculata)

Poisoning via coniine is a tame death compared to that of the toxic compound found in Water Hemlock. Water hemlock (Cicuta spp.) is extremely poisonous; it is considered North America’s most toxic plant. Even touching the plant can cause poisoning. Water hemlock has been known to cause death to livestock in as little as 15 minutes. Ingestion of any amount of this plant can result in death or permanent damage to the central nervous system.

The toxin, cicutoxin, is found throughout the plant and is most concentrated in the roots. Nausea, vomiting, and tremors occur within 30-60 minutes of ingestion, followed by severe cramps, projectile vomiting, and painful convulsions; death can occur within a few hours. Ouch. Did I mention that it’s poisonous?

C. bulbifera
C. bulbifera

There are four species of water hemlock in North America:  C. maculata, C. bulbifera, C. douglasii, and C. virosa. They are so-named because they grow in wet meadows, along streambanks, and other wet and marshy areas. All species of water hemlock are highly poisonous. C. maculata (spotted water hemlock) has the most widespread distribution, followed by C. bulbiferia.

From Left to Right: C. maculata, C. bulbifera, C. virosa, C. douglasii
From Left to Right: C. maculata, C. bulbifera, C. virosa, C. douglasii

Most accidental cases of poisonings by water hemlock are due to its resemblance to the edible water parsnip, sium suave. A very unfortunate resemblance, indeed. With all the wild edible plants that are available, I believe I will just leave this one in the water.

However, the edible Queen Anne’s Lace (also known as wild carrot, Daucus carota) can be readily distinguished from poison hemlock and water hemlock, so long as you know what to look for. (Make the distinction at your own risk and PLEASE never harvest a plant if you aren’t 100 percent sure of what you are harvesting.)

All of these plants have similar umbels of white flowers. However, Queen Anne’s lace often has a single dark flower in the center as a distinguishing feature. If you see this, you can be certain of the identification.

Queen Anne’s Lace

Another defining characteristic is the stems. Queen Anne’s lace has hairy stems, whereas all species of hemlock have smooth, hairless stems. Spotted hemlock has characteristic purple splotches or streaks on the stem.

Left to Right: Water Hemlock, Poison hemlock, and Queen Anne's lace
Left to Right: Water Hemlock, Poison hemlock, and Queen Anne’s lace

If you are planning on harvesting and eating Queen Anne’s lace, the final indicator is the smell. The whole plant smells like a carrot. If you crush the stem a little, you will smell it. If it does not smell like a carrot, it is not Queen Anne’s lace. DO NOT EAT IT. And wash your hands.

Fool’s parsley (Aethusa cynapium)

Fool's Parsley (Aethusa cynapium)

Fool’s parsley, another poisonous lookalike, can cause pain and vomiting, as well as a burning sensation in the mouth and throat. It can be identified by the long beard-like bracts that hang below the secondary flower clusters.  It can be distinguished from Queen Anne’s lace by the lack of hairs on the stem.

fools parsley1
Fool’s Parsley (Aethusa cynapium)

Water hemlock identification: ontariowildflowers.com

Poison hemlock identification: ontariowildflowers.com

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