This is the fruit of the oak tree called acorn and the seed of the oak tree.

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The acorn is the willow tree is also known as the oak genus of plants nuts, shaped like a cocoon, so it is also known as chestnut cocoon. Acorn exterior hard shell, brownish red, inner kernel such as peanut kernels, rich in starch.

Oak, also known as oak or quercus. Shell bucket family of plants, including the genus Quercus, Cycads and species of the genus Coleus, usually refers to the genus Quercus, non-specific reference to a particular species of trees. The genus Quercus has 615 species, of which 450 are from the subgenus Quercus and 188 are from the subgenus Quercus glauca. Its fruit is called acorns, and the wood is known generically as oak.

Deciduous or evergreen trees, up to 25 to 30 meters high or more. Bark dark gray-brown, slightly smooth. Branchlets brown, glabrous.

Winter buds long ovate, 3 to 5 mm long, glabrous, bud scales dark brown, numerous, imbricate. Leaf blade ovate or elliptic, 10-20 cm long, 7-10 cm wide, apically acuminate, base cuneate, leaf margin 5-7-pinnatipartite on each side, lobes finely dentate, leaf surface dark green, leaf abaxial surface light green, glabrous or with tufts of hairs in the vein axils; petiole 2.5-5 cm long, glabrous with age.

Staminate inflorescences open at the same time as the leaves, several clustered; female flowers solitary or 2~3 borne on a raceme ca. 1 cm long.

Shell cupular, enclosing 1/4-1/3 of nut, 1.5-1.8 cm in diam. and 1-1.2 cm in height; bracteoles triangular, densely imbricate, glabrous and shiny. Nut long ellipsoid, ca. 1.5 cm in diam. and 2-2.5 cm in height, light brown, thinly tomentose, gradually glabrescent; apical part rounded, with a stylopodium; umbilicus flat or slightly concave. Fruiting flat or slightly concave. Native to the Americas. This species is resistant to water and moisture. The nut contains 46.1% starch, 10.6% tannin, 12.6% oil, 7.4% protein.