By virtue of its simple, dry fruit, clover belongs to the plant family Leguminosae, and by virtue of the structure of its flower to the subfamily Faboideae. The latter possess the property, thanks to the nodule bacteria in their root system, of fixing atmospheric nitrogen, and hence improving the fertility of the soil. Alongside this general chemical function of clover in agriculture, which was known in Britain from at least the mid-17th century and elsewhere in Europe by the 18th century at the latest [2. 440 f.]; [10. 110], snail clover (medic) in particular was used as ea…