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Acer japonicum
Shown here is the bright autumn color of A. japonicum 'acontifolium'.
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Sapindales Family: Sapindaceae Genus: Acer Species: A. japonicum
Binomial name
Acer japonicum Carl Peter Thunberg and Johann Andreas Murray, 1784

Acer japonicum is a species of maple native to all of Honshū Island and part of Hokkaidō Island in Japan. It is sometimes called Downy Japanese Maple.

Contents 1 Classification 2 Description 3 Cultivation 4 References

This tree shares the common name "Japanese Maple" with the closely-related A. palmatum, although some cultivars of A. japonicum are known by their own common names (such as the "Grape-leaf maple" A. japonicum 'Vitifolium').^[1]

The Fullmoon Maple is sometimes included as a subspecies of A. japonicum but is more often categorized as its own species, A. shirasawanum.^[1]

Given the variety within each species and their similarity, A. japonicum and A. palmatum are sometimes difficult to distinguish. Cultivars of each variety are, at times, labeled as cultivars of the other. ^[1]

A. japonicum grows to about 12 m (40 feet) tall. In cultivation, it is often a shrubby tree with multiple trunks joining at ground-level. Its roundish leaves are 8-15 cm wide with seven to eleven serrate lobes incised to about half the diameter of the leaf. It flowers in long, drooping purplish-red corymbs that appear in spring before the leaves. Samaras are about 3 cm long and hang under the leaves. ^[1]

In addition to the Grape-leaf maple mentioned previously, other popular cultivars of A. japonicum are 'Aconitifolium' (pictured above) which is characterized by its deeply incised leaves and the lace-like 'Dissectum' which displays this characteristic to an even greater extent.^[1].

In regards to preferred growing conditions, A. japonicum is similar to A. palmatum but is sometimes considered generally more tolerant of cold, especially compared to the more delicate cultivars of the later.^[1]

Cultivars of this maple are found in almost every maple collection including Esveld Aceretum (Boskoop, Netherlands) and the large Acer section of Arnold Arboretum (boston, USA. They are also common in more general collections of horticulture, such as Valley Gardens (Surrey, England).

1. ^ ^{a b c d e f} van Gelderen, C.J. & van Gelderen, D.M. (1999). Maples for Gardens: A Color Encyclopedia.