15. Lithocarpus irwinii (Hance) Rehder, J. Arnold Arbor. 1: 127. 1919.
广南柯 guang nan ke
Quercus irwinii Hance, Ann. Sci. Nat., Bot., ser. 2, 18: 229. 1862; Pasania irwinii (Hance) Oersted; Synaedrys irwinii (Hance) Koidzumi.
Trees ca. 10 m tall. Young branchlets sulcate, densely tawny pilose, glabrescent; lenticels raised. Petiole usually less than 1 cm; leaf blade elliptic to lanceolate, 7-12 × 2-4 cm, thickly and rigidly leathery, abaxially with reddish brown, scurfy, waxy scalelike trichomes and when young sparsely pilose on midvein, adaxially dark brown and often oily when dry, base cuneate and decurrent on petiole, margin entire or undulate from middle to apex and ± recurved, apex acute to acuminate; secondary veins 10-15 on each side of midvein; tertiary veins abaxially very slender, evident to inconspicuous. Male inflorescences solitary in axils of leaves, or 2 or 3 in panicles; rachis tawny pubescent. Female inflorescence with cupules in clusters of ca. 3, sometimes solitary. Infructescences 2-5 cm; rachis 5-8 mm thick. Cupule turbinate, 2-2.6 × 1.8-2.4 cm, completely enclosing nut, apically broadest and ± flat, wall 2-4 mm thick; bracts imbricate, triangular, center and margin thickened in ridges. Nut subglobose, ca. 1.5 cm in diam., densely covered with appressed minute hairs, wall 2-2.5 mm thick; scar covering ca. 1/4 of nut, convex. Fl. Apr-May, fr. Oct-Nov of following year.
* Sparse forests, common in hilly regions S of the Tropic of Cancer; below 400 m. Fujian, Guangdong, Guangxi