Sopewort; a genus of the digynia order, belonging to the decandra class of plants. The most remarkable species is the officinalis, or common sopewort, which grows naturally in many parts of this country. It has a creeping root, so that in a short time it would fill a large space of ground. The stalks are about two feet high, and of a purplish colour. The footstalks of the flowers arise from the wings of the leaves opposite; they contain four, five, or more purple flowers each; which have generally two small leaves placed under them. The stalk is also terminated by a loose bunch of flowers growing in form of an umbel; they have each a large swelling cylindrical empalement, and five broad obtuse petals, which spread open, of a purple colour. These are succeeded by oval capsules with one cell filled with small seeds.—The decoction of this plant is used to cleanse and scour woollen cloths; the poor people in some countries use it instead of soap for washing; from whence it had its name.