Description from Flora of China
Quercus tenuicupula (Y. C. Hsu & H. W. Jen) C. C. Huang.
Trees to 30 m tall. Branchlets whitish, glabrous, slightly sulcate, densely lenticellate; lenticels whitish. Petiole 2-4 cm, black when dry, glabrous; leaf blade oblong to obovate-elliptic, 10-25 × 5-10 cm, papery, glabrous, abaxially grayish green, adaxially glossy-green, base broadly cuneate, margin entire to remotely crenate and apically serrate, apex somewhat caudate; midvein adaxially impressed; secondary veins 9-12 on each side of midvein, abaxially prominent, parallel; tertiary veins abaxially slender, evident. Female inflorescence 2-6 cm; cupules 3-5. Infructescence ca. 10 cm, with 1-5 fruit. Cupule bowl-shaped, ca. 1.5 × 2-4 cm, enclosing ca. 2/3 of nut, outside thinly grayish velutinous, wall ca. 1 mm thick; bracts in 6 or 7 rings, margin undulately denticulate. Nut oblate, 2-2.5 × 2.5-3 cm, apex depressed; scar 2-2.5 cm in diam., flat; stylopodium persistent, slightly raised. Fl. Apr, fr. Sep.
Very close if not identical to Cyclobalanopsis sichourensis; it may no longer be possible to maintain them as separate when additional collections are available.
* 900-1000 m. Yunnan (Jinping Xian)