青楷枫 qing kai feng

Acer pensylvanicum Linnaeus var. tegmentosum (Maximowicz) Wesmael.

Trees to 15 m tall, andromonoecious. Bark dark gray. Branchlets glabrous, glaucous white during winter; winter buds blue, ellipsoid. Leaves deciduous; petiole 4-7(-13) cm, glabrous; leaf blade abaxially pale green, suborbicular-ovate, 10-12 × 7-9 cm, papery, abaxially with yellowish barbed hairs at vein axils, adaxially glabrous, primary veins 5, lateral veins 7 or 8 pairs, base rounded or subcordate, margin doubly serrulate, usually 3- or 5-lobed, rarely with 2 small basal lobes; lobes ovate, apex acuminate. Inflorescence pendulous, racemose, 15-flowered, slender, glabrous. Pedicel ca. 5 mm, very slender. Sepals 5, oblong, ca. 3 × 1.5 mm, apex obtuse. Petals 5, obovate, ca. 3 × 2 mm. Stamens 8, glabrous, rudimentary in pistillate flowers. Disk glabrous, intrastaminal. Ovary glabrous, rudimentary in staminate flowers; style short. Fruit yellowish brown, glabrous; nutlets flat or slightly convex; wing including nutlet 2.5-3 × 1-1.3 cm, wings spreading obtusely or nearly horizontally. Fl. Apr, fr. Sep. 2n = 26.

Coniferous and mixed forests; 500-1000 m. Heilongjiang, Jilin, Liaoning [Korea, E Russia].