Oak family

Thank you Maplemoth for the information.

All species of oak trees, produce acorns. Acorns contain one seed, on rare occasion two seeds, encased in a shell. The acorn, or oak nut, is the nut of the oaks, and there close relatives ( genera Quercus and Lithocarpus, in the family Fagaceae ). It usually contains a single seed ( occasionally two seeds ), enclosed in a tough, leathery shell, and borne in a cup-shaped cupule.

Thank you Karen for the id suggestion.