Acer japonicum Thunb.

A small, bushy, deciduous tree 20 to 30 ft (rarely 40 to 50 ft) in height; branchlets glabrous. Leaves 2 to 5 in. long and wide, roundish in the main, but seven- to eleven-lobed, the lobes ovate or lanceolate, long-pointed, sharply and irregularly toothed; there is a tuft of whitish hairs at the end of the downy leaf­stalk on the upper side, and the under-surface is furnished with whitish hairs on the ribs and in their axils. Flowers purplish red, produced in early April before the leaves in long-stalked clusters. Fruits at first hairy, then glabrous; keys 3⁄4 to 1 in. long; wings 1⁄3 in. wide, spreading nearly or quite horizontally.

Native of Japan. It is best known in cultivation by its garden varieties, of which the following are the commonest:

From the Supplement (Vol. V)

For the cultivars of this species, see Vertrees, op. cit., pp. 134–41.

cv. ‘Aconitifolium’. – It has frequently been questioned whether ‘Aconitifolium’ is really the same clonally as ‘Filicifolium’ (‘Parsonsii’). According to Vertrees, they are indeed different, ‘Filicifolium’ having slightly smaller leaves with narrower lobes and of thinner texture. But he adds that they are really very similar and that, for the nursery trade, ‘the question may be only academic.’

cv. ‘Aureum’. – See A. shirasawanum f. aureum below.

† cv. ‘Green Cascade’. – Leaves deeply divided as in the Dissectum group of A. palmatum; of pendulous habit, needing training when young. Raised in the USA.

A. pseudosieboldianum – Closely related to this and perhaps no more than a local variant is A. takesimense Nakai, which is said to differ from it in having leaves with thirteen or fourteen lobes, more incisely toothed. Introduced by J.G. Harris from the type-locality on Ullung-do (Dagelet Island), off the coast of Korea.

A. sieboldianum – The usual autumn colour in this species is orange and red though yellow in the cultivar ‘Sode No Uchi’.

† A. shirasawanum Koidz. – see A. shirasawanum.

† A. tenuifolium (Koidz.) Koidz. A. shirasawanum var. tenuifolium Koidz. – Very near to A. shirasawanum, but with leaves of a delicate membranous texture, downy beneath at least when young and with persistent axillary tufts. Native of Japan.