The "Oo-momiji" (Acer amoenum) belongs to Aceraceae (the Maple family). It is a tall deciduous tree that is endemic to Japan, where it is widely distributed. This tree grows on sunny montane slopes and can reach 10-15 m in height. The bark is grayish-brown and smooth, though it acquires shallow, longitudinal furrows when old. The leaves are palmately divided into 5-9 lobes with caudal tips. The lobes have fine uniform toothed edges. The compound corymbs are borne on the axils and produce male and bisexual flowers from April to May. The fruits are samaras with wings that open to an obtuse angle. (edit by Greg Brockelbank)