Bur oak or mossycup oak is one of the most majestic of the native North American oaks. It is a medium to large sized deciduous oak of the white oak group with a broad-spreading, rounded crown. Acorn cups are covered with a mossy scale or bur near the rim, hence the common name. In Missouri, it typically occurs in low woods and stream valleys in the Ozark region, but on dry upland soils in the unglaciated parts of the state north of the Missouri River.