Acer palmatum

Acer palmatum is a deciduous shrub or small tree reaching heights of 6 to 10 m (20 to 33 ft), rarely 16 metres (52 ft), often growing as an understory plant in shady woodlands. It may have multiple trunks joining close to the ground. In habit, it is often shaped like a hemisphere (especially when younger) or takes on a dome-like form, especially when matureThe leaves are 4–12 cm long and wide, palmately lobed with five, seven, or nine acutely pointed lobes. The flowers are produced in small cymes, the individual flowers with five red or purple sepals and five whitish petals. The fruit is a pair of winged samaras, each samara 2–3 cm long with a 6–8 mm seed. The seeds of Acer palmatum and similar species require stratification in order to germinate.
Even in nature, Acer palmatum displays considerable genetic variation, with seedlings from the same parent tree typically showing differences in such traits as leaf size, shape, and color. Overall form of the tree can vary from upright to weeping.

Colored leaves of a Japanese maple at the Nison-in temple in Kyoto
Three subspecies are recognised:
Acer palmatum subsp. palmatum. Leaves small, 4–7 cm wide, with five or seven lobes and double-serrate margins; seed wings 10–15 mm. Lower altitudes throughout central and southern Japan (not Hokkaido).
Acer palmatum subsp. amoenum (Carrière) H.Hara. Leaves larger, 6–12 cm wide, with seven or nine lobes and single-serrate margins; seed wings 20–25 mm. Higher altitudes throughout Japan and South Korea.
Acer palmatum subsp. matsumurae Koidz. Leaves larger, 6–12 cm wide, with seven (rarely five or nine) lobes and double-serrate margins; seed wings 15–25 mm. Higher altitudes throughout Japan.