Tree to 18 m, crown umbellate. Bark grey to olive-brown. Branchlets initially smooth and dark brown; later rough and silvery. Leaves deciduous, papery, 8–15 × 7–15 cm, palmately three-lobed or rarely entire or five-lobed, upper surface glabrous, lower surface persistently grey- or yellow-pubescent, especially along the veins, margins entire, lobe apex acuminate or aristate; petiole 5–9 cm long, slender, glabrous, exudes milky sap when broken; autumn colour clear yellow. Inflorescence terminal, racemose. Flowers yellowish, 5-merous, staminate or hermaphrodite; sepals elliptic to oblong, ~0.4 cm long, petals oblong to obovate, same length as sepals, stamens eight, inserted into the nectar disc. Samaras 1–1.3 cm long, yellowish brown when mature, wings spreading acutely or erectly. Flowering April, fruiting September (China). Van Gelderen et al. 1994, van Gelderen & van Gelderen 1999, Xu et al. 2008. Distribution CHINA: northern Guangxi, southern Henan, Hunan, western Hubei, Jiangxi, southern Shaanxi, Sichuan. Habitat Mixed forest in valleys between 300 and 1650 m asl. USDA Hardiness Zone 6–7. Conservation status Not evaluated. Illustration NT89. Cross-references B212, S47 (as A. fulvescens); K80. Taxonomic note The persistent hairs on the undersides of the leaves distinguish A. longipes subsp. longipes from all other members of section Platanoidea.
Van Gelderen et al. (1994) recognised four subspecies of A. longipes, and a key to these is provided below. Xu et al. (2008) recognise A. longipes Franch. ex Rehder and A. amplum Rehder as separate species, with A. amplum having the following subspecies: subsp. amplum (including A. longipes subsp. firmianioides), subsp. bodinieri (H. Lév.) Y.S. Chen, subsp. catalpifolium (Rehder) Y.S. Chen, subsp. tientaiense (C.K. Schneid.) Y.S. Chen. Acer fulvescens Rehder is regarded as a full species.
Leaves pubescent on the lower surface; China (northern Guangxi, southern Henan, western Hubei, Hunan, Jiangxi, southern Shaanxi, Sichuan)
Leaves large, 20 × 28 cm; China (Hubei)
subsp. firmianioides (W.C. Cheng) de Jong
Leaves smaller, 8–25 × 5–15 cm
Leaf blade entire and unlobed, or rarely with two- or three-lobed leaves on the same branchlet; samara 5–5.5 cm long; China (northeastern Guangxi, northern Guizhou, Sichuan)
subsp. catalpifolium (Rehder) de Jong
Leaf blade three- to five-lobed; samara 2.5–4.5 cm long; China (southern Anhui, Fujian, northwestern Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Sichuan, Yunnan, Zhejiang)
subsp. amplum (Rehder) de Jong
Acer longipes is closely related to, and rather resembles the more familiar A. cappadocicum and A. platanoides and can at times match them for size, although in cultivation it seems to be less vigorous. As a common tree in Sichuan (van Gelderen et al. 1994) it is not surprising that it was collected by earlier travellers there, but few trees resulted. One planted at Borde Hill in 1932, possibly derived from Wilson’s collections of 1908 (Wilson 1004, 1162) (Bean 1976a), was grown as A. fulvescens for many years, and provided seed for more recent plantings (van Gelderen et al. 1994). In 1995 it was 13 m, 50 cm dbh (Johnson 2003). A tree planted in 1976 in Park Wood, Hergest Croft, is now approximately 10 m in height, but shows signs of squirrel damage. The name fulvescens appears to refer to the ‘fulvous’ or yellowish brown pubescence that covers the young leaves of this taxon, and persists on the undersides of the mature leaves. More recently A. longipes subsp. longipes has been collected by the various SICH expeditions (SICH 0629, 0731, 1329, 1814, 2087, 2226), and young plants from these gatherings are growing in several collections in the United Kingdom, at Quarryhill, and in Vancouver where they are up to 8 m tall (from SICH 2087, 2226) (P. Wharton, pers. comm. 2007). In Poland it suffers from winter damage and frozen young shoots (P. Banaszczak, pers. comm. 2007). Attractive features of the species are the rich red of the petioles, and its clear yellow autumn colour.
Subsp. amplum was introduced by both Wilson and Forrest, and a few notable specimens are mentioned by Bean (1976a). A Forrest introduction planted in 1937 at Borde Hill was 13 m in 1995 (Johnson 2003). It remains uncommon in cultivation but is represented in major collections. A yellow-leaved selection has been named ‘Gold Coin’ and distributed by Firma C. Esveld, in whose Aceretum the original plant grows as a large shrub. Subsp. catalpifolium is also in cultivation and available in the nursery trade. Wilson 1359, collected in 1908, and his collection 4208 of 1910, are referrable to subsp. catalpifolium and may be the source of some of this material (P. Gregory, pers. comm. 2007). It has large leaves, especially when young, and (as with subsp. firmianioides) these can be weakly lobed. There is a particularly fine one growing at Chevithorne Barton, Devon, 10–11 m tall and c.30 cm dbh in 2006. Subsp. firmianioides, if truly distinct, is apparently not in cultivation.