SCIENTIFIC NAME: Polygonum
COMMON NAME(S): Knotweeds, Smartweeds
FAMILY: POLYGONACEAE - Buckwheat family
ORIGIN: North temperate zone, about 150 spp.
HABITAT: Wetlands, roadsides, disturbed areas
CHARACTERISTICS: Base of leaf stem swollen and sheathing the main stem
LEAVES: Alternate, frequently lance-shaped
FLOWERS: Flowers small, numerous in spikes or branched-flower stems, white, pink, purple or green
FLOWERING SEASON: Variable
FRUITS: Small, dry, hard, 1-seeded
ALLERGENIC PRINCIPLES: Unknown
ALLERGENIC PROPERTIES: Dermatological
COMMENTS: The juice of the plant may cause dermatitis to sensitive individuals. Several dozen species are native to the region.