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Pterocarya rhoifolia Sieb. & Zucc.

Japanese Wing-nut

Modern name

Pterocarya rhoifolia Siebold & Zucc.

A tree 80 to 100 ft high, trunk 8 to 10 ft in girth; young shoots nearly glabrous. Leaves 8 to over 12 in. long, composed of eleven to twenty-one leaflets, which are rounded at the base, pointed at the apex, oblong, finely and evenly toothed, 212 to 4 in. long, 1 to 112 in. wide; common-stalk not winged. The stalk and leaves vary in regard to pubescence, but the plants which grew at Kew were glabrous except for tufts of stellate down about the midrib and axils of the veins beneath; but in Japan a form is commonly much more downy on the leaves and leaf­stalks. Male catkins 3 in. long; females 8 to 10 in. long; wings of the nut horizontal, broadly crescent-shaped, the whole fruit 34 to 1 in. across.

Native of Japan; introduced in 1888. It is quite hardy, and in a moist loam would apparently grow well. Professor Sargent found it abundant on Mt Hakkoda at 2,500 to 4,000 ft above sea-level, and almost the largest deciduous tree in that part of Japan.

The only recorded example of this species is one at Borde Hill, Sussex, measuring 50 × 312 ft (1969).

From the Supplement (Vol. V)

specimens: Borde Hill, Sussex, Lullings Ghyll, 62 × 4 ft (1977); Singleton Abbey, Swansea, a superb tree, 71 × 614 ft (1982); Birr Castle, Co. Offaly, Eire, 42 × 234 ft, 42 × 234 ft and 42 × 314 ft (1985).



Other species in the genus