| Ring-cupped Oak | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fagales |
| Family: | Fagaceae |
| Genus: | Quercus |
| Species: | Q. glauca |
| Binomial name | |
| Quercus glauca (Thunb.) |
|
Quercus glauca (syn. Cyclobalanopsis glauca, Q. annulata), also known as Ring-cupped Oak, Japanese Blue Oak or Glaucous-leaf Oak, is a species in the genus Quercus, native to Asia from Afghanistan east to southern Japan (アラカシ;粗樫), Taiwan (青剛櫟), and Vietnam.
It is a small to medium-sized evergreen broadleaf tree growing to 15-20 m tall. The leaves are a distinct deep purple-crimson on new growth, soon turning glossy green above, glaucous blue-green below, 6-13 cm long and 2-5 cm broad, with a serrated margin. The flowers are catkins, and the fruit are acorns 1-1.6 cm long, with an intricate ring pattern on the acorn cup.
It is planted as an ornamental tree in regions of Europe and North America with mild winters.