It is a herbaceous biennial plant that grows to 1.5–2.5 m, with a smooth, green, hollow stem, usually spotted or streaked with red or purple on the lower half of the stem. All parts of the plant are hairless (glabrous). The leaves are two- to four-pinnate, finely divided and lacy, overall triangular in shape, up to 50 cm long and 40 cm broad. The flowers are small, white, clustered in umbels up to 10–15 cm across. When crushed, the leaves and root emit a rank, unpleasant odour often compared to that of parsnips. It produces a large number of seeds that allow the plant to form thick stands in modified soils.
The toxicity of the plant has inspired many of its common names: In addition to the English poison hemlock, the Australian Carrot Fern, and the Irish devil's bread or devil's porridge, poison parsley, spotted corobane, and spotted hemlock are used.
Eight piperidinic alkaloids have been identified in C. maculatum. Two of them, gamma-coniceine and coniine, are generally the most abundant, and they account for most of the plant's acute and chronic toxicity. Due to high potency, the ingestion of seemingly small doses can easily result in respiratory collapse and death.
Coniine causes death by blocking the neuromuscular junction in a manner similar to curare; this results in an ascending muscular paralysis with eventual paralysis of the respiratory muscles which results in death due to lack of oxygen to the heart and brain. Death can be prevented by artificial ventilation until the effects have worn off 48–72 hours later. For an adult, the ingestion of more than 100 mg (0.1 gram) of coniine (about six to eight fresh leaves, or a smaller dose of the seeds or root) may be fatal.
In ancient Greece, hemlock was used to poison condemned prisoners. The most famous victim of hemlock poisoning is the philosopher Socrates. After being condemned to death for impiety and corrupting the young men of Athens, in 399 BC, Socrates was given a potent infusion of the hemlock plant. Plato described Socrates' death in 'Phaedo'.
This post is part of the Floral Friday Fotos meme,
and also part of the Friday Greens meme.