Translations:Benutzer:Arian/Klett-Mini-Test/1404/en

The entire foliage, the square, hollow-stemmed stalk, and the flowers are covered in stinging hairs. These are single-celled outgrowths of the epidermis, reinforced at the base by deposits of lime. They carry at their tip a silicified head, which snaps off at the slightest touch. The stinging hair pierces the skin like a hypodermic needle and releases a toxic cell sap that causes the burning sensation — *urticin*. This contains, among other things, substances (*histamine*, *serotonin*, *acetylcholine*) that normally occur only in human beings and animals. In the stinging hairs, a physiological process dies into the periphery of the plant — exactly as is characteristic of the blossom. One can therefore say with full justification: not only have the flowers of the stinging nettle been drawn down into the foliage, but its above-ground shoot is clothed from earliest youth in a kind of flowering process by the stinging hairs themselves.