First, the basic explanation:

Second, a brief introduction:

Corylus heterophylla? Fisch.): Also known as hazelnut, it is one of the four largest dried fruits (walnut, almond, hazelnut and cashew) in the world. It is a shrub or small tree of Corylus in betulaceae with gray bark; Branches are dark gray and hairless; The leaves are oblong or broadly obovate, with concave or truncated tips, triangular tips at the center and irregular double serrations at the edges; Petiole sparsely pubescent or subglabrous; Male inflorescence solitary; The bract is bell-shaped, densely pubescent and sparsely villous, the upper part is lobed, the lobes are triangular, and the margin is entire; Peduncle densely pubescent. Nuts subglobose, glabrous or only sparsely villous at the top. Born in thickets on shady slopes of mountains at an altitude of 2-1m.