枹丝锥 bao si zhui

Quercus calathiformis Skan in F. B. Forbes & Hemsley, J. Linn. Soc., Bot. 26: 508. 1899; Lithocarpus calathiformis (Skan) A. Camus; Pasania calathiformis (Skan) Hickel & A. Camus; Synaedrys calathiformis (Skan) Koidzumi.

Trees 5-10(-20) m tall. First-year branchlets black, dark black-brown, or dusky when dry, glabrous. Leaves spirally arranged, yellowish brown to gray; petiole 1-2.5 cm; leaf blade oblong to obovate-elliptic, very variable in size, often 15-25 × 5-9 cm, thickly papery, covered with brown-red slightly adnate small lamellate waxy scalelike trichomes when young, base cuneate, margin from base to middle undulate and crenate, apex acute, acuminate, or rounded; midvein adaxially raised; secondary veins 20-28 on each side of midvein or rarely fewer. Female inflorescences usually borne more toward apex of branches and if axillary then solitary, 8-16 cm. Infructescences 10-20 cm. Cupules yellowish brown to dark grayish brown when dry, cupular, 0.8-1.2 cm in diam., wall ca. 1 cm thick; bracts scalelike, triangular, annular or sometimes imbricate when young, thickened with age, adnate, arranged in 4-7 rib rings, waxy. Nut ovoid to ellipsoid, 1-1.5 cm × 3-6 mm, apically brown-red tomentose; scar basal, 3-6 mm in diam. Fl. Mar-May, fr. Oct-Dec.

Mixed and broad-leaved evergreen forests; 700-2200 m. SE Xizang, S Yunnan [Laos, Myanmar, N Thailand, N Vietnam]

Castanopsis calathiformis, C. cerebrina, C. fissa, C. longzhouica, C. sclerophylla, and C. uraiana form a group of related species with 1 flower per cupule, and cupule bracts reduced to scales. The first two species are also united by having plicate cotyledons, and the latter three by having flat-convex cotyledons.