A deciduous tree, which will probably ultimately attain a height of 50 ft and upwards; young branchlets minutely downy. Leaves 3 to 51⁄2 in. wide, about three-fourths as long, five-lobed, heart-shaped at the base, dark green and shining above, paler and downy beneath, becoming glabrous later except for tufts in the axils of the veins; lobes ovate, with a long apex. Flowers in erect, corymbose panicles, 2 to 4 in. long. Fruits downy; keys 11⁄4 in. long; wings 1⁄3 in. wide, almost horizontal.
A maple of garden origin with an obvious affinity to A. campestre, especially in the five-lobed leaf having milky sap in the stalk and in the downy horizontally-spreading keys. The leaves, however, are larger, and the lobes more angular. It is probably a hybrid between that species and either A. cappadocicum or A. lobelii. There are two specimens at Kew, planted in 1871, one 55 × 61⁄2 ft and the other slightly smaller (1965); at Westonbirt, Glos., planted 1929, it is 38 ft high; and at the Glasnevin Botanic Garden, Dublin, 45 × 43⁄4 ft (1966).
From the Supplement (Vol. V)
In the first printing the synonym was incomplete. It should read: A. neglectum Lange, not Hoffmannseg.
specimens: Kew, between Temperate House and Lake, pl. 1906, 56 × 51⁄2 ft (1979); Winkworth Arboretum, Surrey, 46 × 51⁄4 ft (1983); Westonbirt, Glos., pl. 1929, 52 × 61⁄2 ft at 2 ft (1982); Spetchley Park, Worcs., 60 × 43⁄4 ft (1981); Thorp Perrow, Bedale, Yorks., 46 × 43⁄4 ft (1981); Abbeyleix, Co. Laois, Eire, 80 × 63⁄4 ft (1985).