Iowa State Tree - Bur Oak - Quercus macrocarpa
Leaf: Alternate, simple, 5 to 8 inches long, oblong in shape with 7 to 11 bristle-tipped lobes.
Flower: Staminate flowers borne on catkins. Pistillate flowers borne on spikes. Appears with the leaves in April or May.
Fruit: Acorns are 3/4 to 1 inch long and nearly round. The cap is flat and thick, covering about 1/4 of the acorn. Matures in 2 years, ripens August to late October.
Twig: Quite stout, red-brown and glabrous. Terminal buds are multiple, quite large, ovoid, and covered with red-brown, mostly hairless scales.
Bark: On young stems, smooth. Older bark develops wide, flat-topped ridges and shallow furrows. The shallow furrows form a pattern resembling ski tracts.
Form: A medium-sized to large tree that develops a short trunk and round crown
when open grown, straight with a clear bole when grown with competition.
Photos courtesy: Michael Aust, John Baitey, Ctaude L. Brown, Bruce Bongarten,
Susan D. Day, Edward C. Jensen, Richard E. Kreh, Larry H. McCormick, Alex X.
Niemiera, John A. Peterson, Oana Popescu, John R. Seiter, David W. Smith, Kim
C. Steiner, James E. Ward, Rodney E. Will, Shepard M. Zedaker.
Text written by: John R. Seiter, Edward C. Jensen, Or John A. Peterson