11. Acer truncatum Bunge, Enum. Pl. China Bor. 10. 1833.
元宝枫 yuan bao feng
Acer cappadocicum Gleditsch subsp. truncatum (Bunge) A. E. Murray; A. laetum C. A. Meyer var. truncatum (Bunge) Regel; A. lobelii Tenore subsp. truncatum (Bunge) Wesmael; A. lobulatum Nakai; A. lobulatum var. rubripes Nakai; A. pictum Thunberg subsp. truncatum (Bunge) A. E. Murray; A. pictum var. truncatum Chin S. Chang; A. platanoides Linnaeus var. truncatum (Bunge) Gams; A. truncatum var. acuminatum X. M. Liu; A. truncatum var. beipiao S. L. Tung; A. truncatum f. cordatum S. L. Tung; A. truncatum var. nudum Schwerin.
Trees 5-10 m tall, andromonoecious. Bark grayish brown or dark brown. Branchlets slender, glabrous; winter buds ovoid. Leaves deciduous; petiole 3-9 cm, glabrous, rarely puberulent at base when young; leaf blade abaxially pale green, adaxially dark green, 8-12 × 5-10 cm, papery, abaxially reticulate, glabrous, rarely with tufts of hairs at vein axils when young, adaxially glabrous, base usually truncate or rarely subcordate, usually 5-lobed, rarely 7-lobed; lobes triangular-ovate or triangular- lanceolate, 3-5 × 1.5-2 cm, margin entire, apex acuminate or caudate-acuminate. Inflorescence erect, corymbose; peduncles 1-2 cm, slender, glabrous. Pedicel ca. 1 cm, slender. Sepals 5, oblong, 4-5 mm, apex obtuse. Petals 5, oblong-obovate, 5-7 mm. Stamens 8, 2-3 mm in staminate flowers, shorter in pistillate flowers, glabrous, inserted near inner margin of disk. Disk slightly lobed. Ovary in fertile flowers compressed; style ca. 1 mm, glabrescent. Infructescence corymbose, pendulous, each with 3-10 fruit. Nutlets flat, thick, 1.3-1.8 × 1-1.2 cm, glabrous; wing greenish white, usually ca. as long as nutlets, rarely longer, parallel on both sides, wings spreading at obtuse or right angles. Fl. Apr, fr. Aug. 2n = 26.
Forests; 400-1000 m. Gansu, Hebei, Henan, Jiangsu, Jilin, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi [Korea].
One of us (Chang) treats this as Acer pictum subsp. truncatum; however, two of us (Chen and de Jong) believe that A. pictum and A. truncatum differ in fruit, bark, and leaves, and de Jong notes that the seeds of A. truncatum are larger, with an exceptionally high percentage of fat and with hypogeous germination.