櫟屬常綠喬木，臺灣原生，日本及南韓亦有分佈。因葉背灰白色而命名。樹皮灰色並生有顆粒狀小皮孔。幼葉與小枝被淡褐色短毛。葉革質，披針形、長橢圓狀披針形至長橢圓形，先端尾狀至銳尖，基部銳尖至鈍，上半部銳鋸齒緣，上表面有光澤。花單性，雌雄同株。雄花下垂葇荑狀；雌花2~3朵成短穗狀花序，子房三室，柱頭三叉。殼斗杯狀，密被灰褐色毛，具5~7環鱗片。

An evergreen tree in the genus Quercus, native to Taiwan and distributed in Japan and South Korea. Its Chinese common name comes from the whitish gray underside of leaves. Bark gray, with small granular lenticels. Leaflets and branchlets are coated with pale brown short hairs. Leaves leathery, lanceolate, oblong-lanceolate to oblong, apex caudate to acute, base acute to obtuse, upper half sharply serrated, and upper surface glossy. Flowers unisexual, monoecious. Male catkins drooping; 2-3 female flowers formed short spikes, ovary 3-loculed, stigma trifid. Cupules cup-shaped, densely covered with gray-brown hairs, with 5-7 annular scales.

喜強日照，以富含有機質排水良好的土壤為佳。以種子繁殖為主。

The plants thrive in full sun conditions and soils with rich organic matter and good drainage. Mainly propagated by seeds.

可做庭園景觀樹、行道樹。野生動物的食物。

The plants can be planted as garden landscape trees, street trees and food for wildlife.