Quercus phellos, commonly called willow oak, is a medium to large, deciduous oak tree of the red oak group that is noted for its oak shape, willow-like leaves and relatively fast growth rate. It is native to the Southeastern United States, typically being found in moist bottomland soils. In Missouri, it is usually found in wet or low woods bordering swamps, streams and canals in a few counties in the far southeastern portion of the state (Steyermark). Willow oak typically grows 40-75’ tall with an oval to rounded crown, but may reach 100’ in ideal conditions. Smooth-edged, bristle-tipped, narrow, green leaves (to 5” long and 1” wide) are willow-like. Leaves turn an undistinguished yellow-brown or dull gold in fall. Fruits are rounded acorn cups (to 1/2” long). Acorns can be an important source of food for wildlife. Insignificant monoecious yellowish-green flowers in separate male and female catkins appear in spring (April) as the leaves emerge. Dark, irregularly-furrowed trunks (gray to dark gray-brown) develop on mature trees.