Acer carpinifolium Sieb. & Zucc. Hornbeam Maple Native to Japan, cultivated in some collections. Grows to 15m (50ft) in Japan but hardly ever reaches more than 10m (33ft) elsewhere. Flowers open in late April, early May in clusters 10-12cm (4-4¾in) long. Fruit have down curved wings about 1.5cm (3/5in) long. Leaves are unlike any other maple being more akin to a horn beam leaf, though are opposite rather than alternate as on hornbeams. They turn rich shades of brown and yellow in autumn. Z5.