Giant Sunflower (Helianthus giganteus) growing in an open meadow at Big Hollow Recreation Area in Des Moines county, Iowa.

Details: 

(Top)  Canon EOS 10D,  shutter 1/750 second, aperture f16, ISO 400, Canon EF 100 mm macro lens, no flash

(Bottom)  Canon EOS 10D,  shutter 1/500 second, aperture f13, ISO 400, Canon EF 100 mm macro lens, no flash

Selected References:

Thieret John W, Niering William A, and Olmstead Nancy C. National Audubon Society Field Guide to North American Wildflowers, Eastern Region. New York: Alfred A. Knopf, Inc. Plate 276, P 396.

USDA-NRCS. "Plant profile for Helianthus giganteus." The PLANTS Database (http://plants.usda.gov/ ). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. 2004. <http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=HEGI > (15 Sep. 2004).