Northern Prairie Wildlife Research Center
Southern Wetland Flora
Field Office Guide to Plant Species
Helianthus annuus L.
- Family: Aster (Asteraceae)
- Flowering: July-November
- Field Marks: This robust
sunflower has flower heads up to 12 inches across.
- Habitat: Prairies, disturbed soil, wet meadows.
- Habit: Robust annual herb.
- Stems: Upright, branched, rough-hairy, up to 15 feet tall.
- Leaves: Alternate, simple, the lowermost sometimes opposite, broadly ovate, pointed at the tip,
rounded or heart-shaped at the base, coarsely toothed, rough-hairy on both surfaces, with 3 main
veins, up to one foot long.
- Flowers: Many crowded into large heads, with 1 or more heads per plant; each head 3-12 inches
across, subtended by many green bracts; flowers of 2 kinds: the outer yellow and ray-like; the inner
tubular, dark purple or brown, forming a disk.
- Sepals: 0.
- Petals: Some yellow, ray-like, up to 3 inches long; others dark purple or brown, 5-lobed, tubular.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes oblong, flat, usually hairy, up to 1/2 inch long.
- Notes: This plant is often grown as an ornamental or as a crop plant. The seeds are edible and
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