Illinois State Tree
Leaf: Alternate, simple, oblong to ovate in shape, pinnately veined with an evenly lobed margin, 4 to 7 inches long. The apex is rounded and the base is wedge-shaped. Leaves are hairless, bright green above and whitish below.
Flower: Male flowers are green, borne in naked catkins, 2 to 4 inches long. Female flowers are reddish and appear as single spikes. Appearing with the leaves.
Fruit: Ovoid, but may be oblong, with a warty cap that covers 1/4 of the fruit. The cap always detaches at maturity. Matures in one year, ripens 120 days after pollination (July to September).
Twig: Red-brown to somewhat gray, hairless, with red-brown multiple terminal buds that are small, rounded and hairless. Twigs are often shiny or somewhat glaucous.
Bark: Whitish or ashy gray, varying from scaly to irregularly platy or blocky. On older trees smooth patches are not uncommon.
Form: A large tree; when open grown, white oaks have rugged, irregular crowns that are wide spreading, with a stocky bole. In the forest crowns are upright and oval.
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