26. Castanopsis tonkinensis Seemen, Bot. Jahrb. Syst. 23 (Beibl. 57): 55. 1897.
公孙锥 gong sun zhui
Trees 10-20 m tall. Branches glabrous. Petiole 1-2 cm; leaf blade lanceolate, 6-13 × 1.5-4 cm, membranous, abaxially greenish and sparsely covered with reddish brown, small, lamellate, waxy scalelike trichomes when young, glabrous at maturity, adaxially deep green, base narrowly cuneate, decurrent on petiole, and symmetric or slightly oblique, margin entire, apex caudate to sometimes shortly acute; midvein adaxially somewhat impressed and villous but glabrescent; secondary veins 9-13 on each side of midvein. Female inflorescence ca. 20 cm. Cupule broadly ellipsoid, ovoid, or rarely subglobose, 2-3 cm in diam., dark brownish black when dry, outside glabrescent, wall 0.5-1 mm thick; bracts spinelike, rarely entirely covering cupule, 6-10 mm, glabrescent. Nut 1 per cupule, narrowly conical to broadly ellipsoid, 0.9-1.2 cm in diam., densely brown pilose; scar basal, 8-9 mm in diam. Fl. May-Jun, fr. Sep-Oct of following year.
Broad-leaved evergreen forests; below 2000 m. Guangdong, SW Guangxi, Hainan, SE Yunnan [NE Vietnam]
Most Chinese collections are var. tonkinensis, but some specimens from Guangxi and SE Yunnan may be var. laocaiensis Luong, which has broader and thicker leaf blades, and bracts of cupules thicker and shorter than those of var. tonkinensis.