HORSETAIL/SHAVE GRASS (EQUISETUM ARVENSE) – INTRODUCTION
Horsetail, or shave grass, is to be found as a rampant weed growing chiefly in damp clay and sandy soil, on railroad tracks, unfilled ground, on meadows and alongside paths in the fields. In former times this silica-containing plant was used to clean tinware in some areas of Europe. There are more than twenty varieties in Switzerland, although only Equisetum arvense is used for medicinal purposes. Some varieties are even poisonous, for example Equisetum heleocharis which contains a toxic alkaloid called equisetin. This variety is larger than the common horsetail and, like Equisetum palustre, a marsh plant, it should never be used as a medicinal herb. In the remote past shave grass grew considerably taller, attaining the height of a tree, as has been proved by fossilised specimens dug up from the earth.
Today we must content ourselves with the small, rather delicate plant. It has a finely wrought structure and it stands like a tender young fir, pliant yet tough. A flood can knock it to the ground and drag it from its roots, but the little horsetail takes root anew and stands erect. What gives it this toughness and resilience? If we analyse its ash constituents, we will find that it contains 60-65 per cent silica and 15 per cent calcium, with the balance of 20 per cent being made up of other minerals.
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