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A deciduous tree to 12 m. Bark dark brown, smooth. Branchlets purplish green to olive-brown, glabrous and waxy. Leaves subcoriaceous, broadly ovate in outline, 8–17 × 7–15 cm, palmately three- to five-lobed, lobes shallow, upper surface glabrous, lower surface glabrous but for the tufts of hair in the vein axils, margins entire or occasionally dentate (serrate in young leaves), apex acute; petiole 2–3.5 cm long, purplish green; autumn colour orange-yellow to red. Inflorescence terminal, paniculate, 8–10 cm long, many flowered. Flowers 5-merous, usually dioecious; sepals triangular, purplish green, petals yellowish, stamens 8, inserted inside the nectar disc, ovary pubescent. Samaras 1.8–3 cm long, yellowish, wings spreading horizontally. Flowering April to May, fruiting September (China) (van Gelderen et al. 1994; Xu et al. 2008).
Distribution Myanmar China Guangxi, southern Guizhou, southeast Xi-zang, southeast Yunnan Thailand Vietnam
Habitat Mixed forest between 300 and 1800 m asl.
USDA Hardiness Zone 8-9
RHS Hardiness Rating H3
Conservation status Near threatened (NT)
Taxonomic note van Gelderen et al. (1994) recognised two subspecies with somewhat larger leaves: subsp. kwangsiense, with leaves 12–17 cm across with sparse teeth on the margin (cultivated by Plantentuin Esveld under glass in the Netherlands); and subsp. liquidambarifolium, with evenly lobed leaves 8–14 cm across. However, these subspecies are not accepted by Xu et al. (2008), whose more recent treatment is followed here.
Acer tonkinense is extremely rare in cultivation and has not been seen in any collections visited in the research for New Trees. Such little information as can be gleaned suggests that it is not hardy in most of our area and must be maintained under glass. It has, however, recently been offered commercially, most notably by Heronswood Nursery in their 2002 catalogue. The plants offered were grown from seed supplied by James Waddick of Kansas City, Missouri, obtained from Shanghai Botanic Garden, and were described as having thick leathery leaves, each of the five lobes terminating in a long-acuminate point. At Heronswood it proved ‘very hardy’ and formed a notable feature with ‘ashen lime’ stems in winter (Heronswood Nursery catalogue 2002). It comes into growth early in the year (D. Hinkley, pers. comm. 2007).