Wild sunflower (Helianthus annuus)

Common Names: Annual sunflower, common sunflower, sunflower

Description: This plant releases chemicals that kill off surrounding vegetation.

Habit: Widely branching, stout annual growing up to 8 ft. tall, with coarsely hairy leaves and stems.

Leaves: Alternate, large, 8 in. long, 6 in. wide, droop downwards from long petioles; cordate, ovate-cordate or ovate with fine dentate margins; upper surface is dull green and covered with short stiff hairs. Petioles are light green to reddish green, covered with short stiff hairs and upper surface is channeled.

Stems: Central stem is light green to reddish green, terete and covered with stiff spreading hairs.

Flowers: Daisy-like, 1/8 in. across, central disk florets that are yellow to brown in color, 20-40 ray florets that are yellow in color. Floral bracts are dull green, stiffly hairy and ovate in shape.

Fruit and seeds: Disk florets are replaced by a large seed that is ovoid and somewhat flattened.

Habitat: Native to North America. Can be found in disturbed sites, abandoned fields, pastures, roadsides, along railroads, and waste areas.

Reproduction: By seed and has a tendency to form colonies.

Credits: The information provided in this factsheet was gathered from Illinoiswildflowers.info.

Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org). Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).

---