Ring Cup Oak

Cyclobalanopsis glauca is part of a widespread complex, with a number of segregate species of uncertain status having been named. Additional studies are needed to clarify the relationships and specific limits within this complex. The status of C. globosa Lin & Liu (Bull. Taiwan For. Res. Inst. 110: 27. 1965), from Taiwan, is uncertain. It is very close to C. glauca and is probably not sufficiently distinct to be recognized as a separate species.

Trees to 20 m tall. Branchlets glabrous. Petiole 1-3 cm; leaf blade obovate to oblong-elliptic, 6-13 × 2-5.5 cm, often wider apically from middle, leathery, abaxially often becoming pruinous and with prostrate white simple or scalelike hairs but glabrescent, adaxially glabrous, base rounded to broadly cuneate, margin apical 1/2 remotely serrate, apex acuminate to somewhat caudate; secondary veins 9-13 on each side of midvein; tertiary veins abaxially inconspicuous. Infructescences 1.5-3 cm, with 2 or 3 fruit. Cupule bowl-shaped, 6-8 mm × 0.9-1.4 cm, enclosing 1/3-1/2 of nut, outside white puberulent or glabrous, inside white sericeous; bracts in 5 or 6 rings, crowded, margin entire or denticulate. Nut ovoid, oblong-ovoid, or ellipsoid, 1-1.6 × 0.9-1.4 cm, glabrous or rarely hairy; scar ca. 5 mm in diam., flat or slightly convex. Fl. Apr-May, fr. Oct.

Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Afghanistan, Bhutan, N India, Japan, Kashmir, Korea, Nepal, Sikkim, Vietnam]

Broad-leaved evergreen forests and mixed mesophytic forests on mountain slopes or in valleys; below 100-2600 m.

Quercus glauca Thunberg in Murray, Syst. Veg., ed. 14, 858. 1784; Cyclobalanopsis glauca var. kuyuensis (J. C. Liao) J. C. Liao; C. repandifolia (J. C. Liao) J. C. Liao; Q. glauca var. kuyuensis J. C. Liao; Q. longipes Hu; Q. repandifolia J. C. Liao; Q. sasakii Kanehira; Q. vaniotii H. Léveillé.