Vernicia fordii (tung tree, "Oaburagiri")

Japanese name: オオアブラギリ （大油桐）
Scientific name: Vernicia fordii

[Overview]
A deciduous tree about 10 m tall.
The bark is grayish brown and smooth.
Leaves are alternate, either simple or shallowly three-lobed in the upper part.
On mature trees the leaves are often unlobed.
The leaves are ovate-heart-shaped, 5–18 cm long and 3–15 cm wide, with a pointed tip.
The underside is pale green and covered all over with fine brown hairs.
The leaf margin is almost entire and sometimes wavy.
The leaf stalk is 6–26 cm long, and two stalkless glands are located at the base of the leaf.
There are male flowers and female flowers.
Both male and female inflorescences are panicles borne at the branch tips.
Both male and female flowers are white, five-petaled, 2.5–3.5 cm across, with petals 2–3 cm long, and the bases of the petals have purplish-brown streaks.
The fruit is a flattened spherical capsule 4–6 cm in diameter.
The fruit has no grooves or ridges, ends in a sudden point, and does not split open when ripe.
Each fruit contains 4–5 seeds.

[History]
It was cultivated to obtain oil from the seeds, and has become naturalized.

[Uses]
The oil obtained from the seeds is called tung oil (kiri-abura), and is used industrially for paint, printing ink, and polishing furniture and lacquerware.
This oil is toxic and is not edible.
The extract from the bark contains tannin and seems to have been used for tanning leather and as a dye for fishing nets.

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