Description from Flora of China
Acer laxiflorum var. dolichophyllum W. P. Fang; A. pectinatum Wallich ex G. Nicholson subsp. laxiflorum (Pax) A. E. Murray.
Trees to 15 m tall, andromonoecious. Bark smooth. Branchlets slender, glabrous; winter buds oblong or ellipsoid, glabrous, scales 2 pairs. Leaves deciduous; petiole 4-7 cm, pubescent; leaf blade abaxially pale green, adaxially dark green, ovate, 7-14 × 5-8 cm, papery, adaxially glabrous, veins 9-11 pairs, base cordate or subcordate, margin sharply serrulate with adpressed teeth, 3-lobed, rarely 5-lobed; middle lobe long acuminate at apex; lateral lobes small, apically acute; basal lobes obsolete. Inflorescence terminal on leafy branchlets, pendulous, racemose, less than 10-flowered, ca. 4 cm, glabrous, appearing after leaves. Pedicel slender, glabrous. Sepals 5, oblong, glabrous, apex obtuse. Petals 5, greenish yellow, obovate, narrowed at base, apex obtuse. Disk glabrous, intrastaminal. Stamens 8, glabrous, rudimentary in staminate flowers. Ovary glabrous; style ca. 1 mm; stigmas recurved. Fruit brownish yellow when mature; nutlets flat, ca. 8 mm in diam.; wing including nutlet 2.5-2.7 × ca. 1 cm, wings spreading obtusely or nearly horizontally. Fl. Apr, fr. Sep. 2n = 26*.
● Mixed forests; 1800-2500 m. Sichuan, Yunnan.