What kind of walnut is the iron walnut? An introduction to the latest walnut varieties
The iron walnut, also known as the Yangbi walnut, is a deciduous tree in the genus Juglans of the family Juglandaceae, distributed in southwestern China and other places. Its fruit has a hard shell. At first, the iron walnut was mainly used for oil pressing and as rootstock for ordinary edible walnuts. Now many new uses have gradually been developed. It can be used to make various beautiful and durable handicrafts. In some places, large and oddly shaped iron walnuts are also selected for use as fitness balls; their uneven shells can massage the acupoints of the hands and have a certain health-care effect.
The iron walnut tree is 10-20 m tall and can live for more than a hundred years. The trunk bark is grayish brown to dark brown, with vertical fissures. New branches are light green and smooth, with white lenticels. The leaves are odd-pinnately compound and alternate. The female inflorescence is terminal, with small flowers clustered in groups of 2-4. The fruit is round and yellow-green, covered with fine hairs on the surface, and contains 1 seed inside. The outer seed coat is bony and is called the shell; its surface is dotted, and the shell varies in thickness.
The iron walnut has strong graft compatibility and vigorous growth, but poor cold resistance. It adapts to a subtropical climate. Its production areas are mainly Yunnan, Guizhou and Sichuan. With an extreme minimum temperature of -2°C, it cannot overwinter in northern regions. In the Taihang Mountains, its yield is lower than that of the Qiuzi walnut. However, because of factors such as production area altitude, climate and rainfall, the iron walnut of the Taihang Mountains is clearly different from that of the south, which also causes differences between northern and southern iron walnuts in size, shape and other aspects.
Iron walnuts are mostly used by scholars and refined collectors for handling and play, and are called wenwan iron walnuts. The reason players like them is probably their large size, strange shapes and relatively low price. While being used as objects for handling and play, they are also carved by folk artisans into art treasures highly favored by players. Artisans carve the images and patterns of various animals and figures on the small walnuts, placing beautiful meanings in them and expressing people's expectations and longing for the future.
The shapes of iron walnuts are indeed rich and varied, including various cap types and head types, and there are also many abnormal forms, such as Buddha's belly, toad head, eagle beak, duck bill, jujube pit, double petal, triplet, three-ridged and multi-ridged forms, and so on. Some shapes are extremely bizarre and have no conventionally established names, and they have great value for handling and play. The textures include honeycomb texture, snake skin texture, dense texture and so on, and the tip types include cross tip, blunt tip, beak-like tip, needle-like tip and so on.