Aralia elata and Catalpa bungeana have thorns, but Aralia elata is distributed in the northern part of China, and mostly grows on hillsides and river valleys. At the initial stage of growth, the fruit is turquoise, then gradually turns black, and there will be slender straight thorns of about 2 cm on the branches.

Catalpa bungeana mostly grows in plain and hilly areas and likes warm and humid environment. Does not require much soil, and can grow tenaciously in rural sandy soil. Moreover, the thorns of Catalpa bungeana are very hard and sharp, and there will be obvious burning sensation when you plunge into them.