1. Uncaria rhynchophylla: dry hooked stem, slightly square, about 2 cm long and about 2 mm in diameter, with reddish-brown or tan surface, a ring-shaped stem node at one end, slightly protruding, and two pairs of opposite hooks at the node, such as ship anchor, with inward curling or single hook at the top, different sizes, slightly round base and 2-2 in diameter. It is light and hard, and it doesn't break easily. The outer layer of the section is brownish red, the pith is light yellow, and it is as loose as a sponge. No breath, light taste. It is best to have double hooks, such as anchor, thin stem, solid hook, slippery hook, reddish brown or purple brown. Location: Guangxi, Jiangxi, Hunan, Zhejiang and Guangdong.

2. Uncaria rhynchophylla: The character is similar to Uncaria rhynchophylla. However, the stems and branches are square columns with a diameter of about 2 ~ 3 mm, a gray-brown surface and a slightly wider hook base. Location: Sichuan, Guizhou, Yunnan, Hubei and other places. The hooked stems and branches of Uncaria also have many uses, mainly including: ① Uncaria verticillata with narrow wings; The hook is smooth. ② Uncaria-shaped, with smooth hooks and narrowly triangular stipules. ③ Uncaria macrophylla, see Uncaria macrophylla. (4) Uncaria pubescens, with coarse hairs on branches, hooks and leaves. Uncaria sessilifolia, the corolla tube is hairless, the lobes are densely covered with silk, and the branches are sparsely covered. ⑥ The climbing stems, branches and hooks of Uncaria are densely pilose, and the leaves are villous below.

In spring and autumn, pick the shoots with hooks, cut off the stems without hooks and dry them in the sun, or steam them in a pot and dry them in the sun.

The chemical constituents of the leaves and branches of Uncaria rhynchophylla stem include rhynchophylline, isorhynchophylline, corynoxine alkaloid, isorhynchophylline alkaloid, concanavaline, dihydroconcanavaline, fiber caryophylline and fiber caryophylline.