Acer maximowiczianum Miq.

A deciduous tree to 20 m. Bark grey, smooth, becoming somewhat rough and occasionally plated with age. Branchlets glabrous. Buds ovoid, acutely-tipped, with 11 to 15 pairs of imbricate, pubescent scales. Leaves trifoliolate, subcoriaceous, elliptic to oblong in outline; leaflet bases cuneate, leaflets 7–20 × 3–6 cm, elliptic to ovate, apically acute (to acuminate), margins often undulate, entire to remotely and shallowly serrate, upper surface mid green, pubescent at first, becoming glabrous, lower surface paler, pilose, densely so along veins, sessile or petiolule very short, longer on central leaflet, pubescent; petiole 3–5 cm long, green to purplish, densely pubescent; autumn colours yellow and orange to purple. Inflorescence corymbose, pendulous, 3–5-flowered. Flowers yellowish green, 5-merous, usually functionally dioecious, peduncles ~ 0.2 cm, pubescent, pedicels pilose, 0.5–1 cm long on pistillate flowers, 2 cm long on staminate flowers, sepals obovate, petals the same length as sepals, oblong-obovate, pale green, stamens 8–14, slightly protruding from flower, inserted on the inner margins of the nectar disc, ovary pubescent. Samaras usually to 3.5–4 (–6) cm long, wings spreading at right angles. Nutlets +/- rounded, pubescent. Flowering April to May, with unfolding leaves, fruiting in September to October. (Bean 1976; van Gelderen et al. 1994; Ogata 1999; Xu et al. 2008).

Distribution  China Southern Anhui, western Hubei, Hunan, northern Jiangxi, eastern Sichuan, northwestern Zhejiang Japan Honshu (west from Miyagi and Yamagata Prefectures); Kyushu, Shikoku.

Habitat In China, in mixed forests between 1000 and1800 m asl; in Japan, in deciduous forests between 500 and 1500 m asl.

USDA Hardiness Zone 4-7

RHS Hardiness Rating H7

Awards FCC

Conservation status Least concern (LC)

Taxonomic note Confusion around the correct name of this species is long-standing, with the name Acer nikoense persisting in gardens, and erroneously used in the 2008 account of the species in the Flora of China (Xu et al. 2008). The species had indeed been known under that name for 100 years before Murray (1969) asserted that A. maximowiczianum was the correct name. His treatment was followed by de Jong (1976), Clarke (1988) and van Gelderen et al. (1994), who each provided justification for doing so, summarised as follows from the aforementioned sources and correspondence with Piet de Jong: A. nikoense and A. maximowiczianum were both described in 1867, the former by Maximowicz, the latter by Miquel. A. nikoense was described a month earlier than A. maximowiczianum, and thus ordinarily would have taken priority. However, the material of Maximowicz’s A. nikoense turned out not to be a maple at all, but in fact belongs to a species of Parthenocissus. In determining the material of his maple, Maximowicz included as a synonym Negundo? nikoense, using a question mark to indicate uncertainty as to this placement. Two years earlier, Miquel had described Negundo nikoense from Japanese material that was supposed to be from a maple, and to which Maximowicz was referring, but instead this material belonged to Parthenocissus tricuspidata, as determined at Leiden in 1966. Though the determination of Maximowicz’s A. nikoense as a maple has never been disputed, Miquel’s Negundo nikoense is considered as the type of the name A. nikoense Maxim. Later, Miquel noted himself that his Negundo nikoense was not the same species as described by Maximowicz under A. nikoense and thus proposed the name A. maximowiczianum, under which the species should now be known. In between various treatments supporting the (correct) use of A. maximowiczianum, Delendick (1980) re-stated the case for A. nikoense, and the name evidently persisted. However, Delendick later agreed that A. maximowiczianum was (and is) the correct name (van Gelderen et al. 1994), though unfortunately did not manage to publish a correction before he died. The confusion has been resolved, though, and the name of the Nikko Maple confirmed as A. maximowiczianum.