Bearded Maple - Acer barbinerve [1]
Pubescent veins on the undersides of leaves; hence its Latin species epithet barbinerve, which means "bearded veins".
Also commonly called hairy-veined maple or ussuri maple.
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"Shrubs or small, multistemmed trees, to 7 m tall, dioecious. Bark grayish yellow or grayish brown, smooth. Young branchlets puberulent, becoming nearly glabrous and dull reddish brown in second year; bud scales 2 pairs. Leaves deciduous; petiole 4-6 cm, slender, puberulent when young, glabrescent; leaf blade suborbicular or ovate, 8-10 × 6-8 cm, membranous, abaxially hirsute-pubescent especially on veins, adaxially glabrous, primary veins 5, base cordate or subcordate, margin doubly serrate with coarse obtuse teeth, 5-lobed, rarely 7-lobed; middle and lateral lobes acuminate apically; basal lobes acute. Inflorescence racemose, lateral from leafless buds. Pedicel 1-2 cm, slender, glabrous. Staminate racemes very short, ca. 1.5 cm, 5- or 6-flowered; sepals 4, oblong, slightly ciliate along margin, ca. 5 mm; petals 4, rhombic-obovate, slightly shorter than sepals; stamens 4, ca. as long as sepals, glabrous, absent in pistillate flowers; disk 4-lobed, glabrous, intrastaminal; ovary absent or very rudimentary in staminate flowers. Pistillate racemes with slender peduncle ca. 4 cm, puberulent, usually 7-flowered; sepals oblong, ca. 4.5 mm, ciliate, with long hairs at apex; petals obovate, nearly as long as sepals, distinctly clawed; ovary glabrous; style ca. 2 mm, glabrous; stigmas revolute. Infructescence pendulous, racemose, ca. 5 cm. Samaras 5-7; nutlets subglobose, ca. 10 × 8 mm, rugose, strongly veined; wing introrsely falcate, slightly contracted at base, including nutlet 3-3.5 cm, wings spreading obtusely.Native to China, it is found in mixed forests at 1000-1600 m. elevation. --www.efloras.org, Flora of China

References

1. Hairy-veined Maple, Morton Arboretum acc. 157-91*2, photographed October 19, 2009 by Bruce Marlin

2. eFloras.org, Flora of China, "Hairy-veined Maple - Acer barbinerve."
3. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN)
   "Acer barbinerve Maxim."