Polyg'onum Bistor'ta, Bistort. -- Europe, Asia, N. America, in meadows. Produces an S-shaped rhizome, bent upon itself -- bistorted. 5 Cm. (2') long, 15 Mm. (3/5') thick, flattened or channeled, upper side transversely striate, root-scars on under side, red-brown; contains tannin 20 p.c., starch, calcium oxalate, tonic, astringent. Dose, gr. 5-30 (.3-2 Gm.)