Quercus bicolor Willd.
Tree, 15 - 30 m tall, trunk 0.66 - 1 m in diameter. Form oval and open. Bark reddish brown and peeling when young, becoming grayish brown and deeply fissured with flattened ridges. Twigs changing from shiny green and reddish brown to peeling and dark brown. Buds light to dark brown, 2 - 4 mm long, egg-shaped to almost spherical with a rounded tip. Each terminal bud is surrounded by a cluster of lateral buds. Leaves alternate, short-stalked, shiny dark green above, pale green to silvery white and hairy beneath, 12 - 18 cm long, 5 - 12 cm wide, inversely egg-shaped with a wedge-shaped base, coarsely round-toothed or shallowly lobed. Foliage turns yellowish brown to orange in fall. Flowers either male or female, found on the same plant (monoecious). Male flowers are borne in hanging catkins, yellowish green, and 7 - 10 cm long, while female flowers are borne in small clusters near leaf axils. Fruit an acorn, developing in one season, usually in pairs, sometimes solitary, with a 2.5 - 10 cm long stalk. The bowl-shaped cup covers one-quarter to half of the nut and has scales that are thicker near the base with a lightly fringed margin. Nut light brown, 2 - 3 cm long and oblong to almost cylindrical.
[adapted from vPlants.org]
Many oaks in the white oak group and Quercus robur have highly variable, similar leaves with rounded lobes. Quercus alba often has deeply lobed leaves, light gray bark usually with smooth patches, and an acorn cup covered with warty scales. Quercus lyrata has leaves that are inversely egg-shaped with irregular, rounded lobes, and an acorn cup that nearly covers the nut. Quercus macrocarpa has deeply lobed leaves that are inversely egg-shaped and hairy beneath, often corky-ridged twigs, and an acorn cup with long fringes along the margin. Quercus robur has very short-stalked leaves with ear-like lobes at the base, and a long-stalked acorn cup.
Quercus bicolor naturally hybridizes with Q. macrocarpa (Q. x schuettei).
Ecology and Distribution
Locally common in lowlands, moist woods, floodplains, near swamps, and in poorly drained uplands.
- Quercus alba var. palustris Castigl. (synonym)
- Quercus bicolor var. angustifolia Dippel (synonym)
- Quercus bicolor var. cuneiformis Dippel (synonym)
- Quercus bicolor var. mollis Nutt. (synonym)
- Quercus bicolor var. platanoides (Castigl.) A.DC. (synonym)
- Quercus discolor var. bicolor (Willd.) Hampton (synonym)
- Quercus filiformis Muhl. ex A.DC. (synonym)
- Quercus mollis Raf. (synonym)
- Quercus paludosa Petz. & G.Kirchn. (synonym)
- Quercus pannosa Bosc ex A.DC. (synonym)
- Quercus platanoides (Castigl.) Sudw. (synonym)
- Quercus prinus var. bicolor (Willd.) Spach (synonym)
- Quercus prinus var. discolor F.Michx. (synonym)
- Quercus prinus var. platanoides Castigl. (synonym)
- Quercus prinus var. tomentosa Michx. (synonym)
- Quercus velutina L'Hér. ex A.DC. (synonym)