bur oak Fagaceae Quercus
Leaf: Alternate, simple, 6 to 12 inches long, roughly obovate in shape, with many lobes. The two middle sinuses nearly reach the midrib dividing leaf nearly in half. The lobes near the tip resemble a crown, green above and paler, fuzzy below.
Flower: Species is monoecious; male flowers are yellow-green, borne in long, drooping slender catkins, 2 to 4 inches long; female flowers are green tinged in red and appear as single, short spikes, both appear shortly after the leaves.
Fruit: Acorns are quite large (1 1/2 inches long) and 1/2 enclosed in a warty cap that has a long-fringed margin, maturing in one growing season in late summer and fall.
Twig: Quite stout, yellow-brown, often with corky ridges; multiple terminal buds are small, round, and may be somewhat pubescent often surrounded by thread-like stipules; laterals are similar, but smaller.
Bark: Ashy gray to brown in color and quite scaly, but noticeably ridged vertically on large trees.
Form: A large tree that often reaches over 100 feet tall with a long clear bole. In the open it becomes a very wide, spreading tree.
Looks like: white oak - overcup oak - post oak - sand post oak
Additional Range Information: Quercus macrocarpa is native to North America. Range may be expanded by planting. See states reporting bur oak.
More Information: Fall Color - Landowner Factsheet
External Links: USDAFS Silvics of North America - USDAFS Additional Silvics - USDA Plants Database - Horticulture Information - USDAFS Forest Products Lab
All material © 2017 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson