Description from Flora of China
Quercus hypophaea Hayata, Icon. Pl. Formosan. 3: 182. 1913; Lithocarpus hypophaeus (Hayata) Hayata; Pasania hypophaea (Hayata) H. L. Li.
Trees to 18 m tall. Branchlets slender, whitish hairy. Petiole 0.5-10 mm, triangular in cross section, densely gray tomentose; leaf blade narrowly elliptic-lanceolate, 5-9.5 × 1.5-2.3 cm, subleathery, abaxially whitish tomentose and hairs adnate, adaxially bright green, base cuneate, margin entire, apex acuminate; midvein abaxially prominent and adaxially flat; secondary veins 8-14 on each side of midvein, slender, evident, not fusing; tertiary veins abaxially obscure. Cupule saucer-shaped, 5-8 mm × 1-1.8 cm, outside whitish pubescent; bracts in 7-11 rings. Nut oblate to broadly ovoid, 1.7-2.1 × 1.2-1.8 cm; scar 5-8 mm in diam., slightly convex. Fl. Dec-Jan, fr. Jan-Feb of following year.
* Broad-leaved evergreen forests; near sea level to 1100 m. SE Taiwan