Polygonum bistorta, Linn. (BistOrta officinalis, Raf). Bistort. Snakeweed. Perennial, with a thick more or less spreading rootetock: st. simple, slender but strict, 1-2 ft.: lvs. mostly radical,oblong-ovate and obtuse, undulate, glaucous beneath; st.-lvs. nearly sessile, broad at base; stipules 1/2—3 in. long: fls. white or pink, in a single dense cylindrical or oblong spike an inch or two long; stamens exserted; styles 3. N. Eu. and N. Asia. —The astringent rootstock was once used medicinally, and has provided food in famine times. Var. superbum, Hort., is offered abroad, with conical heads of bright pink long-lasting fls.