Species: Quercus suber

Cork is an impermeable buoyant material, the phellem layer of bark tissue that is harvested for commercial use primarily from Quercus suber (the cork oak), which is endemic to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic biopolymer.

Because of its impermeable, buoyant, elastic, and fire retardant properties, it is used in a variety of products, the most common of which is wine stoppers.