Acer rufinerve (Snake-bark Maple)
Species: A. rufinerve
Binomial name: Acer rufinerve
Synonyms: Acer tegmentosum subsp. glaucorufinerve
Common names: Snake-bark maple, Redvein Maple, Honshu Maple
Acer rufinerve is a maple in the snakebark maple group. Snakebark maples are maples belong to the taxonomic section Acer sect. Macrantha. The section includes 18–21 species, and is restricted to eastern Asia (the eastern Himalaya east to Japan) with the exception of one species in eastern North America. The various species of snakebark maples are most easily distinguished from other maples by their distinctive bark, smooth (at least on young trees), and usually patterned with vertical dark green to greenish-brown stripes alternating with stripes of light green, pinkish or white, sometimes with a bluish tone.
Acer rufinerve is native to mountains forests of Japan, on Honshu, Kyushu and Shikoku.
This is one of the most commonly planted snakebark maples, and is a hardy, fast grower. It is a small deciduous tree growing to a height of 8–15 m, with a trunk up to 40 cm diameter. The bark on young trees is smooth, olive-green with regular narrow vertical pale green to grayish stripes and small grayish lenticels; on old trees, it becomes rough and grey. The leaves are three-lobed (occasionally five-lobed with two additional small basal lobes), double serrated, 8-16 cm long and 6-16 cm broad, matt to sub-shiny dark green above, paler below with small tufts of rusty hair on the veins when young, becoming glabrous when mature; the petiole is greenish (rarely pinkish), 3–5 cm long. The leaves turn to bright orange or red in the autumn.
The flowers are produced in racemes 10 cm long, each flower 8–10 mm diameter, with five yellow to greenish-yellow sepals and petals; it is dioecious, with male and female flowers on separate trees. The fruit is a paired samara 2–3 cm long with rounded nutlets.