Uncaria rhynchophylla var. rhynchophylla ("Kagikazura")

Japanese name: カギカズラ （鉤葛）
Scientific name: Uncaria rhynchophylla var. rhynchophylla

[Overview]
An evergreen woody climber found in evergreen forests and at forest edges.
The vines extend more than 10 m.
At each node there is a thick, sharp, fishhook-shaped curved thorn; with these thorns it climbs trees and rocks, and when they twine around something they thicken and serve to anchor the plant.
The thorns are modified side branches, and usually one and two appear alternately at successive nodes.
Young branches are square in cross section.
The leaves are simple and opposite, 5–12 cm long and 3–6 cm wide, ovate to oblong, with a sharply tail-like pointed tip and an entire margin.
The upper surface of the leaf is glossy and the underside is tinged powdery white; usually the leaf is hairless except for the midrib and vein axils on the underside.
Young leaves are reddish.
The petiole is 0.3–2 cm long and has 4 linear stipules that fall early.
At the tip of a stalk 2–4.5 cm long extending from a leaf axil, a spherical flower head 1.5–2 cm across bears many flowers.
The flowers are pale green; the corolla is slender and salverform, about 0.4–0.7 cm long, 5-lobed, with rounded lobe tips.
There are 5 stamens, about as long as the corolla, and the pistil protrudes far out of the flower, with a club-shaped stigma.
The fruit is an elliptical capsule, and the seeds are small, 0.5 mm, with slender wings at both ends.

[Uses]
The thorns are used as a crude drug called chotoko.

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