About Acer truncatum Bunge
Acer truncatum Bunge, commonly called Shantung maple, Shandong maple, or purpleblow maple, is a maple species native to northern China (found across the provinces of Gansu, Hebei, Henan, Jiangsu, Jilin, Liaoning, Inner Mongolia, Shaanxi, Shandong, Shanxi) and Korea. It is a medium-sized deciduous tree that grows up to 15 metres (49 ft) tall, developing a broad, rounded crown. The bark is greenish-grey and smooth on young trees, becoming shallowly ridged or grooved as the tree ages. Its leaves are arranged oppositely, are palmately five-lobed, and measure 5 centimetres (2.0 in) to 12 centimetres (4.7 in) long and 7 centimetres (2.8 in) to 11 centimetres (4.3 in) broad, growing from a petiole 3 centimetres (1.2 in) to 10 centimetres (3.9 in) long. The lobes are most often smooth-edged, though the largest central lobe occasionally has a pair of teeth, and the leaf margin is often wavy. When broken, the petiole releases milky latex. Its yellow-green flowers with five petals 5 millimetres (0.20 in) to 7 millimetres (0.28 in) long grow in corymbs, and flowering occurs in early spring. The fruit is a double samara made of two winged seeds. The seeds are disc-shaped, slightly flattened, and 13 millimetres (0.51 in) to 18 millimetres (0.71 in) across. The 2 centimetre (0.79 in) long wings are widely spread, forming an angle approaching 180°. This species is resistant to drought and heat. It is closely related to Acer amplum, Acer cappadocicum, and Acer pictum subsp. mono, which replace it further south and west in China and in Japan, and is often difficult to distinguish from these relatives. It can be told apart from Acer cappadocicum by its shoots, which turn brown by their first winter instead of remaining green for multiple years. It can be distinguished from Acer mono (synonym A. pictum auct. non Thunb.) by its larger, thicker, less flattened seeds. Very unusually for maples, Acer truncatum exhibits hypogeal germination. Shantung maple is cultivated as an ornamental plant in Europe and North America. A number of cultivars have been selected: these include 'Akikaze Nishiki', which has variegated leaves, and 'Fire Dragon', which has very bright autumn color. The cultivar 'Keithsform', sold as Norwegian Sunset, is a hybrid between Acer truncatum and Acer platanoides (Norway Maple).
