Iowa State Tree – Bur Oak – Quercus macrocarpa
Leaf: Alternate, simple, 5 to 8 inches long, oblong in shape with 7 to 11 bristle-tipped
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
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.
Conservation; Photos and text by: John Seiler, Edward Jensen,
Alex Niemiera, and John Peterson;Silvics reprinted from Ag
Handbook 654; range map source information