Quercus macrocarpa

The bur oak is in the white oak group (Quercus) in the beech or Fagaceae family, and is native to eastern and central United States and eastern and central Canada, north and west to the southern end of Lake Winnipeg. Among the white oaks, it is one of the most tolerant of urban conditions, and is one of the fastest-growing of the group.

• Leaves are alternate, simple, 7–15 cm long and 5–13 cm broad, variable in shape, with many lobes. Most often, the basal 60% is narrower and deeply lobed, while the apical 40% is wider and has shallow lobes or large teeth.
• Species is monoecious. Male flowers are greenish-yellow catkins up to 10 cm long. Female flowers are green tinged in red, single on short spikes, both produced in the spring.
• Twigs are stout, yellow-brown, often with corky ridges, with multiple small terminal buds.
• Acorns are very large, 2–5 cm long and 2–4 cm broad, having a large cup that wraps much of the way around the nut, with large overlapping scales and often a fringe at the edge of the cup. The acorns are the largest of any North American oak.