Stinging plant

Stiff hairs or trichomes without the ability to inject irritating compounds occur on the leaves and stems of many plants.

They appear to deter feeding insects to some degree by impeding movement and restricting access to the surface of the stem or leaf.

[3] Stinging hairs may be defined as those with ability to inject a chemical substance through the skin of an animal causing irritation or pain.

[3] The general structure of a stinging hair is very similar in all the families of plants that possess them (except Tragia and Dalechampia).

Each hair contains a fine tube, stiffened with calcium carbonate (calcified) at its base and with silica (silicified) at its tip.

[9] The stinging sensation is initially caused by the mechanical entry of the stiff hair into the skin, but is then intensified by the effect of the oxalate.

Fu et al. concluded that "stinging hairs, although studied for a long time, are still mysterious, particularly concerning the mechanism of the skin reaction after being stung.

Between twenty-four and thirty-nine species of flowering plants of the genus Urtica in the family Urticaceae fall into this category, with a cosmopolitan though mainly temperate distribution.

[citation needed] The family Urticaceae also contains some other plants with stinging hairs that are not members of the genus Urtica.

One recorded human death is known: a lightly clad young man died five hours after walking through a dense patch.