四蕊枫 si rui feng

Acer betulifolium Maximowicz, Trudy Imp. S.-Peterburgsk. Bot. Sada 11: 108. 1889; A. lauyuense W. P. Fang; A. megalodum W. P. Fang & H. Y. Su; A. tetramerum Pax; A. tetramerum var. betulifolium (Maximowicz) Rehder; A. tetramerum var. haopingense W. P. Fang; A. tetramerum f. latialatum Rehder; A. tetramerum var. lobulatum Rehder.

Petiole 2.5-5 cm, slightly pubescent when young, glabrescent; leaf blade ovate, rarely oblong-ovate or elliptic, 5-10 × 2.5-7 cm, membranous, abaxially glabrous or white pubescent when young, glabrescent, adaxially slightly pubescent when young, glabrescent, base rounded, rarely slightly truncate, margin unequally and incised-serrate, 3-lobed or undivided, apex acuminate or obtuse. Fruit 5-8; nutlets oblong, ca. 8 × 6 mm, rugose; wing oblong, slightly contracted at base, including nutlet 3-5.5 × 1-1.2 cm, wings spreading variously. Fl. Apr-May, fr. Sep.

Alpine forests; 1400-3300 m. S Gansu, W Henan, W Hubei, Ningxia, S Shaanxi, Sichuan, Yunnan [Myanmar].