Snake-Weed or Polygonum, L. a genus of plants comprehending thirty-three species, ten of which are natives of Britain : the following are the principal, namely :

1. The Hydropiper. See WATER-PEPPER.

2. The Persicaria, or Spotted SnakE-weed, abounds in ditches, and watery situations ; though it is sometimes found in corn fields : where it flowers from the month of July to September. This species slightly acid and astringent : it is eaten by goats, sheep, and horses, but refused by bogs and cows. - LinnAEUs informs us, that woollen cloth, previously dipped in a solution of alum, acquires a yellow colour from a decoction of this plant. - Dambourney obtained an olive colour.

3. The Bistorta. See Bistort the Great.

4. The viviparum. See Bistort the Small.

5. The Fagopyrum. See Buckwheat.

6. The Convolvulus. See Buck-Wheat the Climbing.

7. The aviculare, or KNOTGRASS SNAKE-WEED, is found On road-sides, in paths, streets, and corn-fields, particularly in a gravelly soil: it flowers from April to October. - This species of glass is eaten by cows, horses, sheep, goats and hogs : its seeds are a grateful food to small birds of every description; and may likewise be employed for the same purposes as those of Buck-wheat (see vol. i. p. 376) : but sheep, feeding on the knot-grass snake-weed, become, according to Bechstein. liable to obstructions, and consequently to putrid diseases.