A deciduous tree of the largest size, often over 100 ft high in the wild, the trunk occasionally as much as 10 ft in diameter, and forming a broad head of branches; young shoots downy. Leaves oval or obovate, tapered at the base, rounded or blunt at the apex, with four or five rounded lobes at each side, 11⁄2 to 3 in. long, 5⁄8 to 13⁄4 in. wide, dark green and glabrous or nearly so above; pale, dull and downy beneath, especially on the midrib; margin edged with fine hairs; stalk 1⁄8 to 1⁄2 in long, downy. Fruits scarcely stalked; acorns slenderly conical, pointed, 11⁄4 to 2 in. long, mostly solitary, about one-fourth enclosed in the cup.
Native of W. California; introduced to Kew by Bolander in 1874, but possibly in cultivation before. A stately tree in its own country, it has little to recommend it in this, being of exceedingly slow growth and not striking in foliage. It reaches its greatest size on deep moist loam, and in some of the Californian valleys is not infrequently 100 to 150 ft high, with trunks 8 to 10 ft through. Its timber is of poor quality, but many fine trees are preserved in the fields of the West for the sake of the shade their wide-spreading branches afford. A tree at Kew near the Ash collection, pl. 1874, measures 67 × 73⁄4 ft (1967) with a deeply furrowed bark.