Description from Flora of China
Acer diabolicum Blume ex Koch subsp. sinopurpurascens (W. C. Cheng) A. E. Murray.
Trees to 10 m tall, dioecious. Bark brownish gray, nearly smooth. Branchlets of first year green and sparsely pilose, later brownish, glabrescent; buds bright brown, ovoid, with many imbricate scales, scales densely pilose. Leaves deciduous; petiole 4-8.5 cm, slender, pubescent when young, glabrescent; leaf blade abaxially light green, adaxially dull green, abaxially with axillary tufts of hairs between primary and secondary veins, both surfaces densely pilose on veins when young, less so when mature, ciliate at margin, 5-veined from cordate or subcordate or truncate base, 5-lobed, rarely 3-lobed; 2 basal lobes spreading, triangular, margin very remotely dentate or entire, apically acute or acuminate, midlobe oblong-ovate, slightly longer or very rarely shorter than lateral ones, margin very remotely dentate or entire, with margin nearly parallel below middle, apex long acuminate. Peduncle green or purplish, 1-2.5 cm, sparsely pilose, sometimes glabrous. Flowers purple-red, from lateral leafless buds, appearing before leaves. Staminate flowers apetalous, in pendulous racemes or corymbose racemes, 3-7-flowered, embraced by several convex bracts; bracts oblong or oblong-obovate, to 1.2 cm, outside densely pilose, inside glabrous; pedicels purple, 1-2.5 cm, sparsely pilose; sepals (3-)5(or 6), unequal in size, ca. 5 mm, glabrous; petals 5, ca. as long as sepals; stamens 8, inserted inside of disk. Pistillate flowers in pendulous racemes, 3-7-flowered; perianth purple, glabrous; ovary densely pilose; stigma 2-lobed. Fruiting pedicels 8-14 mm, glabrous; samaras slightly ascending at base, with strongly keeled and veined nutlets, ca. 3.6 cm; wings ca. 1 cm wide, sparsely pilose; nutlets pale yellow, ca. 10 × 9 mm, pubescent and bristly. Fl. Apr, fr. Sep.
● Mixed forests; 700-1000 m. S Anhui, NE Hubei, N Jiangxi, NW Zhejiang.