Ring-cup oak
Quercus glauca · Fagaceae · 종가시나무
How to spot it
Identified by 5 to 6 concentric rings on the acorn cup and the inward-curved teeth on the upper half of the leaf.
(original photo, new tab)Leaf · Photo KENPEI · CC BY-SA 3.0 
(original photo, new tab)Leaf · Photo Krzysztof Ziarnek, Kenraiz · CC BY-SA 4.0 
(original photo, new tab)Bark · Photo KENPEI · CC BY-SA 3.0
Look
- Leaves
- Leaves are broad elliptic to obovate-elliptic, 7 to 12 cm long, with inward-curving teeth on the upper half; glossy above and grayish-white beneath.
- Flowers
- Flowers open in April to May; the axis of the male catkin has white hairs.
- Fruit
- The cup is hemispherical, 6 to 9 mm across, with 5 to 6 concentric rings; the nut is ovoid to elliptic and matures in the same year.
- Bark
- The bark is greenish-gray and does not crack.
Where it grows
- In Korea
- Native (Korean Peninsula)
- Native to
- Native to Jeju-do, Korea (foothills and valleys below 600 m) and Oenaro-do, and ranges from the Himalayas (Nepal, Bhutan) to Vietnam, Taiwan and Japan.
- Ecology
- Young trees grow well in partial shade and need more light as they age. It strongly tolerates wind, salt and pollution but is weak against cold. It is a representative tree of warm-temperate forest.