Curlytop knotweed growing along the banks of the Mississippi River in Des Moines County, Iowa..

Details: 

(Top) Canon EOS 10D,  shutter 1/350 second, aperture f11, ISO 200, Canon EF 100 mm macro lens.

(Bottom) Canon EOS 10D,  shutter 1/350 second, aperture f8, ISO 200, Canon EF 100 mm macro lens.

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. P 703.

USDA-NRCS. "Plant profile for Polygonum lapathifolium L."  The PLANTS Database (http://plants.usda.gov/ ). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. 2004. <  http://plants.usda.gov/cgi_bin/topics.cgi?earl=plant_profile.cgi&symbol=POLA4  > (20 Sep. 2005).