Ambrosia psilostachya
Family: Asteraceae
Plant Description: Scented and resinous perennials to 120 cm high with pinnatifid leaves 3-6 cm long, leaves opposite below, alternate above, blades 3.5 inches or longer, lobed only one time; forming colonies. Male and female flowers without corollas, in separate heads (clustered on single receptacles). Male heads hanging downward, about 1/8 inches broad, only the anthers emerging from the enclosing bract; female heads hanging downward, about 1/8 inches tall, the enclosing bracts with a single row of spines around the top and central beak.
Plant Trivia: Pollen is a known allergen; plants are very aggressive. Seeds are edible.
Field Identification:
Occurrence: Common on most soils in pastures, woods, stream bottoms, and waste places.
Bloom Period: June-December
Plant Use:
Key to the species of Ambrosia:
- Leaves gray, mostly entire……………………………………………….A. cheiranthifolia
Leaves green…………………………………………………………………………………………………..2
2. Leaves palmately lobed…………………………………………………………………..A. trifida
Leaves not palmately lobed………………………………………………………………………..3
3. Leaves pinnatifid…………………………………………………………………..A. psilostachya
Leaves 2-pinnatifid…………………………………………………………A. confertijlora
stxflora 