27. Acer flabellatum Rehder in Sargent, Trees & Shrubs. 1: 161. 1905.
扇叶枫 shan ye feng
Acer campbellii J. D. Hooker & Thomson ex Hiern subsp. flabellatum (Rehder) A. E. Murray; A. campbellii var. yunnanense Rehder; A. flabellatum var. yunnanense (Rehder) W. P. Fang; A. gracile W. P. Fang & M. Y. Fang (1966), not Saporta (1867); A. mapienense W. P. Fang; A. shangszeense W. P. Fang & T. P. Soong; A. shangszeense var. anfuense W. P. Fang & T. P. Soong.
Trees ca. 10 m tall, andromonoecious. Bark smooth. Branchlets slender, glabrous; winter buds ellipsoid, margin ciliate, inner scales densely villous outside. Leaves deciduous; petiole to 7 cm, slender; leaf blade abaxially pale green, adaxially dark green, 8-12 cm wide, papery or membranous, abaxially glabrescent except villous on veins and tufts of hairs at vein axils, adaxially glabrous, primary and secondary veins raised on both surfaces, base deeply cordate, usually 7-lobed; lobes ovate-oblong, rarely ovate or triangular-ovate, margin sharply and irregularly serrate with appressed acute teeth, apex acuminate or rarely long acuminate. Inflorescence paniculate, to 5 cm, glabrous; peduncles ca. 3 cm. Pedicel ca. 1 mm, slender, glabrous. Sepals 5, ovate-lanceolate, ca. 3 mm, ciliate along margin, apex acute. Petals 5, obovate, ca. as long as sepals. Stamens 8, glabrous. Disk glabrous, slightly lobed, extrastaminal. Ovary glabrous. Fruit yellowish brown; nutlets convex, subglobose, ca. 6 × 5 mm; wing including nutlet 3-3.5(-4) × 1-1.2 cm, wings spreading horizontally. Fl. Jun, fr. Oct. 2n = 26.
Mixed forests; 800-3500 m. Guangxi, Guizhou, W Hubei, Jiangxi, Sichuan, Yunnan [Myanmar, Vietnam].
One of us (Oterdoom) believes that this taxon is a young form of Acer campbellii because of its identical chemical structure.