Hickory (from Powhatan) is a type of tree, comprising the genus Carya. The genus includes 1719 species of deciduous trees with pinnately compound leaves and big nuts. Five or six species are native to China, Indochina, and India (State of Assam), 11 or 12 are from the United States, two to four are from Canada and four are found in Mexico. Hickory flowers are small, yellow-green catkins produced in spring. They are wind-pollinated and self-incompatible. The fruit is a globose or oval nut, 25cm (0.792.0in) long and 1.53cm (0.591.2in) diameter, enclosed in a four-valved husk, which splits open at maturity. The nut shell is thick and bony in most species, and thin in a few, notably C. illinoinensis; it is divided into two halves, which split apart when the seed germinates.