Keyaki, Zelkova serrata
Keyaki or Japanese Zelkova (Zelkova serrata) is a species of plant native to Japan, Korea, eastern China, and Taiwan. It is also grown in Europe and North America. The first cultivation outside of its native Asia was by Philipp Franz von Siebold, who introduced it to the Netherlands in 1830. There are two different varieties.
This plant is a medium to large deciduous tree that grows from 65 to 115 feet tall. The trunk can be up to 13 feet in diameter, but 7 feet is more common. The bark is smooth gray, becoming flaky and browner on older trees. It has numerous branches, ascending strongly from a short trunk to give a high domed crown. The leaves are 1.2 to 4.33 inches long, up to 2.75 inches broad, and are hairless or fine-haired above and below. The autumn colors of the leaves are orange to red. The flowers are yellow-green and tiny. They are pollinated by the wind. The fruit is a small and nut-like, with a ridged surface.
There are many hybridized variations of this plant. These cultivars include Green Veil, Green Vase, Spring Grove, Village Green, Urban Ruby, and others. The wood of this tree is valued in Japan and often used for furniture. The tree is a symbol of Saitama Prefecture and of Machida City in Tokyo Metropolis District.