Quercus glauca var. glauca (ring-cupped oak, "Arakashi")

Japanese name: アラカシ （粗樫）
Scientific name: Quercus glauca var. glauca

[Overview]
An evergreen tree up to 18 m tall with a trunk up to 60 cm in diameter.
The bark is finely uneven or has shallow vertical cracks.
Young twigs are densely covered with pale brown soft hairs.
Leaves are simple and alternate, oblong, 7–12 cm long, thick and hard.
The upper surface of the leaf at first is sparsely covered with soft hairs, but later becomes hairless and glossy.
The underside is densely covered with fine silky hairs and is grayish white to brownish.
The margin of the upper half of the leaf has coarse teeth.
The leaf stalk is 1.5–2.5 cm long.
There are male flowers and female flowers.
The male flowers form catkins 5–10 cm long, densely covered with brown soft hairs, and hang from the lower part of the new shoots.
The female inflorescence stands erect in the leaf axils in the upper part of the new shoots and bears 3–5 female flowers.
The fruit is an ovoid nut (acorn) 1.5–2 cm long that ripens in autumn of the same year.
The cupule (acorn cap) is ring-shaped, with 5–7 rings.

[Uses]
The leaves and bark are used as tanning agents and mordants.

[Cultivation]
Propagate from seed.
The germination rate drops if acorns are allowed to dry, so sow them immediately after collecting, or store them kept moist until spring.
It prefers a sunny, well-drained, fertile soil.
Rainfall is sufficient.
Apply organic fertilizer in winter.
Pests and diseases include powdery mildew and Teppo-mushi (larvae of longhorn beetles).

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