Annual, smooth or somewhat puberulent, stems one-half to 2 feet high, erect or nearly so, simple or branched. Leaves lanceolate or linear-lanceolate, 2 to 6 inches long, nearly sessile, acuminate at both ends, conspicuously dotted, usually with a triangular or lunar dark blotch near the center; ocreae cylindric, fringed with short bristles. Flowers in dense, erect, ovoid or oblong racemes, one-half to 2 inches long, pink to dark purple; stamens usually six.
Native of Europe but naturalized and often an abundant weed in waste places throughout North America, except in the extreme north.
Memoir 15 N. Y. State Museum
b. ladys-thumb; heartweed Persicaria persicaria