A deciduous tree of stately habit, 60 to 90 ft high in Britain, up to 120 ft high in Algeria, with a thick, rugged bark; young shoots ribbed, covered when young with a loose flock, soon glabrous, brown the second year. Leaves oval or obovate, coarsely toothed or lobed, rounded to heart-shaped or auricled at the base, variable in size but usually 31⁄2 to 6 in. long, 2 to 31⁄4 in. wide (often larger on young trees), densely coated on both sides when unfolding with a reddish, floccose tomentum, becoming dark green and quite glabrous above, the underside rather glaucous, also glabrous except for traces of brownish flock on the midrib, especially towards the base and on the stalk, which is 1⁄2 to 1 in. long; ribs in eight to fourteen pairs, fairly straight and regularly spaced. Fruits ripening the first season, scarcely stalked, clustered; acorns about 1 in. long; cup with flattened, downy scales, enclosing the lowest third of the acorn.
Native mainly of N. Africa but also found in the Iberian peninsula, mostly in its southern part. It does not occur wild in the Canary Islands. The date of introduction to Britain is not known, but the oak discussed by Loudon under the queried name Q. australis may well have been Q. canariensis; if so, it was introduced to the garden of the Horticultural Society from the neighbourhood of Gibraltar in 1835. There was an introduction to France by General Pelissier around 1845 by means of acorns, some of which were sent by Louis Philippe to Queen Victoria, who distributed them among the ladies of the court.
Q. canariensis is perfectly hardy, and one of the handsomest of all oaks. It is a vigorous grower and notable for the rich green and large size of its leaves, which remain on the branches until Christmas, sometimes a month or two later. It produces fertile acorns but hybridises so readily with the common oak that its seedlings are rarely true. Fortunately it grows well when grafted on the common or the durmast oak and this is the best way of increasing it if wild-source seed cannot be obtained.
The oldest specimen of the Algerian oak at Kew grows near the Isleworth Gate; it came from Booth of Hamburg in 1869 and measures 74 × 103⁄4 ft (1968). The following are in the main Oak collection: pl. 1882, from the Joad Bequest, 68 × 7 ft (1968); pl. 1895, 66 × 61⁄4 ft (1965) (this tree was bought from Lee’s nursery for half-a-crown and measured 49 × 41⁄2 ft in 1938); pl. 1904, 64 × 53⁄4 ft (1965).
Some of the notable trees in other collections are: Ham Manor, Sussex, two trees mentioned by Elwes and Henry, the larger 70 × 81⁄4 ft (1907), now 76 × 133⁄4 ft (1965); Melbury Park, Dorset, 80 × 101⁄4 ft (1970); Tortworth, Glos., 75 × 10 ft (1965); Osborne, Isle of Wight, 90 × 81⁄4 ft (1964); Howick, Northumb., pl. 1851, 60 × 7 ft (1958); Holker, Lancs, 75 × 12 ft (1971).