SCIENTIFIC NAME: Amaranthus
COMMON NAME(S): Pigweeds, tumbleweeds, waterhemp
FAMILY: AMARANTHACEAE - Pigweed family
ORIGIN: Worldwide, about 60 spp.
HABITAT: Disturbed areas, lawns, roadsides
CHARACTERISTICS: Stems erect, spreading or prostrate
LEAVES: Alternate, simple, often hairy along veins on the underside, frequently glandular, leaf stems long
FLOWERS: Tiny, separate male and female flowers on same or different plants, red or green, borne on congested spikes
FLOWERING SEASON: Spring to fall
FRUITS: Tiny, dry, 1-seeded
ALLERGENIC PRINCIPLES: Pollen allergens
ALLERGENIC PROPERTIES: Respiratory
COMMENTS: These weedy plants are significant contributors to summer and fall pollinosis. Introduced species occurring in the region include Green amaranth (A. hybridus L.), Redroot pigweed (A. retroflexus L.), Spiny amaranth (A. spinosus L.). Prostrate pigweed (A. blitoides) occurs natively throughout the region except Florida.