Origin: Sophora japonica, pinnate compound leaves, small leaves and dense crown. The first lateral branches of Sophora japonica are thicker, so the crown is cloud-shaped. Sophora japonica has rhizobia and abundant nitrogen nutrition, so its leaves are dark green. Seen from a distance, the crown of Sophora japonica is like a thick dark green cloud. Dark green is a kind of dark color, and thick clouds can also bring darkness. The beads of Sophora japonica have constriction marks, and the constriction marks are very thin. The pods of Sophora japonica were stored on the tree. In the rainy season of the next year, when it rained, the scars were soaked by rain and broke, and the peel was soaked and rotted to expose the seeds, which dyed the ground under the shade dark green. Sophora japonica is vulnerable to aphids, and aphid secretions will dye the ground black when they fall to the ground. Therefore, it is often black under the shade of locust trees, which also means darkness. Therefore, the locust tree comes from "darkness". The word "Huai" is similar to the word "Hui" in pronunciation. "Huai" means "Hui tree" and is a tree with a dark crown. It is precisely because of this characteristic of Sophora japonica that people like to hold a cool party under the shade of Sophora japonica. In the Han Dynasty, some people thought that "Sophora japonica means to look forward to it, and people stand under it and think of others far away, wanting to do things with them". This is actually a humanistic explanation of the name of Sophora japonica, because they only noticed the phenomenon that people like to enjoy the cool in the shade of Sophora japonica. Because Sophora japonica is suitable for people to enjoy the cool in the shade, it is also a symbol of status. "Zhou Li Qiu Guan" records that there were three Sophora japonica trees planted outside the court of the Zhou Dynasty. When san huang met the son of heaven, they all stood under the trees. Sangong refers to Taishi, Taifu and Taibao, which are the collective names of the three highest official positions in the Zhou Dynasty. Therefore, later generations used Sanhuai as a metaphor for Sangong, which became a symbol of Sangong's official position, and Sophora japonica became a famous cultural tree species in China.
Seeds black, hilum white or black, concave inward. Similar to black cowpea. When the pod is immature, it will turn yellow, turn black gradually, or rot directly. When the pod turns black, it will crack and the seeds will pop out.