A deciduous round-headed tree 60 or more ft high, described as being of ungainly, unpicturesque habit when old; young shoots stout, densely covered with greyish soft hairs. Leaves amongst the largest of all hardy oaks, occasionally over 1 ft long and 6 or 7 in. wide, the smallest one-third those dimensions, obovate, tapered at the base, blunt or rounded at the apex, the margin with five to nine rounded lobes or deep undulations at each side. When quite young the upper surface is covered with minute down, the undersurface with a whitish felt; but, as the season advances, the down falls away from the upper surface, the lower one remaining sparsely downy. Acorns 1⁄2 to 3⁄4 in. long, rounded; the cup covered with long, narrow, downy scales.
Native of Japan and of the mainland of N.E. Asia; introduced to Europe in 1830. It is a remarkable oak on account of its enormous leaves, but has never been really a success in this country, and is usually short-lived. Its habit is thin and gaunt. The undersurface of its leaves sometimes presents an extraordinary appearance because of an infestation of disk-like galls, so thickly placed as to overlap each other.
At the present time there are two examples of this oak in the collection at Kew, neither of much beauty: one, pl. 1893, is 30 × 21⁄2 ft, the other, pl. 1907, 17 × 11⁄4 ft (1965). It has thrived better at Osterley Park on the other side of the Thames where there is a fine tree measuring 37 × 41⁄4 ft (1965) and another of about the same size. Others recorded recently are: Westonbirt, a crowded tree in Willesley Drive, 50 × 33⁄4 ft (1967); The Grange, Benenden, Kent, 36 × 21⁄4 ft (1972); Trewidden, Cornwall, 40 × 43⁄4 ft (1959); Caerhays, Cornwall, 47 × 41⁄4 ft (1971); Edinburgh Botanic Garden, pl. 1931, 38 × 3 ft (1970).
cv. ‘Pinnatifida’. – A Japanese garden variety with the leaves deeply dissected into narrow, crisped lobes; described in 1879. It is in cultivation in Britain.