Quercus lyrata, the overcup oak, is an oak in the white oak group (Quercus sect. Quercus). The common name, overcup oak, refers to its acorns that are mostly enclosed within the acorn cup. It is native to lowland wetlands in the eastern and south-central United States, in all the coastal states from New Jersey to Texas, inland as far as Oklahoma, Missouri, and Illinois. There are historical reports of it growing in Iowa, but the species appears to have been extirpated there. It is a slow-growing tree that often takes 25 to 30 years to mature. It has an estimated lifespan of 400 years. Description Quercus lyrata is a medium to large-sized deciduous tree, growing as tall as , with an average height of . The trunk averages up to in diameter, or rarely to . It is a slow-growing tree that often takes 25 to 30 years to mature. Quercus lyrata has simple leaves that are alternately arranged. On average, the leaves are inches long. They are broad, deeply lobed, and somewhat lyre-shaped (lyrate). Leaves have a leathery feel. They are dark green and shiny on the top while the underside is a paler gray-green with fine hairs. In autumn, leaf color varies between red, yellow, and brown. Like other oak trees, the overcup oak has clustered terminal buds. The bark is light to dark gray in color with irregular bark plates. Its bark plates are deeply ridged and furrowed. Quercus lyrata has male and female flowers. The male flowers, often brown or yellow in color, form in a drooping, elongated cluster. Female flowers appear as individual reddish spikes with surrounding leaves. The fruit is an acorn. They are generally oval or oblong in shape, ranging from in length. The acorn contributes to the overcup oak's common name. The acorns are almost entirely covered by their cup, hence the name overcup. The cup has gray, pubescent scales. The acorns also have a unique spongy shell that make them buoyant. The pericarp of overcup oak acorns is unusually large for oaks and makes up 50% of acorn mass. The pericarp only makes up 30% of mass in other oak trees. Phenology Quercus lyrata is monecious, producing female and male flowers. Female and male flowers begin to appear in mid-spring around April or May. The male flowers form in a drooping, elongated cluster. They are often brown or yellow in color.