A deciduous tree of the largest size, reaching at its best a height of over 100 ft and a girth of trunk of 20 ft. Bark of the trunk pale, greyish, and peeling off in large flakes; branchlets glabrous. Leaves usually five-lobed (small ones on fruiting twigs often three-lobed), 4 to 7 in. across in adult trees (larger in young ones), heart-shaped at the base; the lobes ovate, coarsely toothed, dark green and glabrous above, paler and dull glaucous beneath, with pale brown hairs in the axils of the veins or, sometimes, along the whole length of the chief ones. Flowers in large drooping racemes, often branching at the base, yellowish green. Fruit on long, pendulous racemes; keys 11⁄4 to 2 in. long; wings glabrous, the two forming an angle of about 60°.
Native of Europe, but not considered to be a true native of Britain, where however, it has existed many centuries and has thoroughly established itself. Judging by the way seedlings spring up in the wilder parts of Kew Gardens, it would seem that in course of time the place, if left to run wild, would become a forest of common sycamore. It is a peculiarly hardy tree, and one of the few that will stand the full force of salt-laden winds in exposed places near the sea. One may see it in many of the gardens on the sea-fronts of English watering-places, battered and stunted in growth, yet helping largely to form that first line of defence against the winds, the establishment of which is really the most important item in the seaside planting. When fully grown it is a magnificent tree of stately proportions, thriving better perhaps in the north of England and in Scotland (where it is known as the ‘plane’) than in the warmer south. Early in this century there was an ancient tree in the grounds of Scone Palace, near Perth, reputed to have been planted by Mary Queen of Scots. Although still alive, most of its upper growth had gone, but its trunk was more than 6 ft through. Mr R. F. Adam, Factor of the Scone Estate, tells us that what remained of this tree was blown down about 1940-1, at which time it was little more than an ivy-covered stump. He adds that the Queen planted a maple on precisely the same spot in 1967. H. J. Elwes, in Trees of Great Britain and Ireland, wrote (1908) that in Scotland ‘I have seen none to surpass in size, shape and perfection the one which I figure … in front of Newbattle Abbey’. He gave the size as about 95 ft high by 16 ft 6 in. in girth at 5 ft. This noble tree still exists; its height, however, is 90 ft, and its girth, measured at an old 5 ft mark, is 16 ft 4 in. (1966).
Among English trees Elwes gave the palm to one at Studley Royal in Yorkshire, then (1908) 104 ft high and 171⁄2 ft in girth. This tree has not been traced and the tallest now on record for England are two at Cobham Hall, Kent, measuring 110 × 191⁄4 and 96 × 141⁄4 ft (1965). Others of size are: Gwydyr Castle, Caer., 90 × 161⁄4 ft (1966); Biel, E. Lothian, 105 × 131⁄2 ft (1967); Hagley Castle, Worcs., 90 × 15 ft (1966); and Holywell Hall, Lincs., 85 × 191⁄2 ft (1966).
The foliage of the sycamore has no autumn beauty, decaying a dingy brown; it is frequently attacked by the tar-spot fungus Rhytisma acerinum, which causes yellow or pale spots to appear on the leaf-blade in June that turn black towards the fall of the leaf. The timber is white, and easily worked.
The sycamore has produced very many varieties and forms under cultivation, some as seedling variations, others as branch sports. It is not necessary to enumerate more than the most distinct of them.
cv. ‘Atropurpureum’. – Leaves dark green above, rich purple beneath. Späth’s nurseries, 1883. Also known in the trade as ‘Purpureum Spaethii’. Forms of this nature, but with the colouring less rich, have probably arisen many times and may breed more or less true from seed. The purple sycamore described by Loudon (as var. purpureum) was stated by him to have originated in Sander’s nursery, Jersey, in 1828. The cultivar name ‘Purpureum’ would belong to the clonal descendants of this tree; the group name for sycamores of this sort is f. purpureum (Loud.) Rehd.
cv. ‘Aucubifolium’. – Leaves blotched with yellow like the common aucuba. It appeared among seedlings in the nursery of Little and Ballantyne at Carlisle, about 1876.
cv. ‘Brilliantissimum’. – A very handsome variety with leaves of a beautiful pinkish hue on unfolding; slow-growing. There is a good example at Powis Castle near Welshpool, 21 ft high with 15 ft diameter of spread (Journ. R.H.S., Oct. 1962).
cv. ‘Corstorphinense’. – Leaves pale yellow when young, golden in early summer. The original tree grew at Corstorphine, near Edinburgh. James Baillie, second Lord Forrester, is said to have been murdered by his sister-in-law at the foot of this tree, 26th August 1679 (Garden and Forest, 1893, p. 202). What is probably the original tree still exists and measures 55 × 121⁄4 ft (1968). There is a specimen at Myddelton House, Enfield, Middlesex, 80 × 6 ft (1957), and another at Studley, Yorks., 60 × 53⁄4 ft (1966).
f. erythrocarpum (Carr.) Pax – Fruits red; said to be wild in the Alps of Bavaria, but the tree on which the name is founded arose in a French nursery (Rev. Hort., 1864, p. 171) and the cultivar name ‘Erythrocarpum’ belongs to this clone. The Pilrig ‘plane’ has similarly coloured fruits, but they are smaller and on longer racemes than in ‘Erythrocarpum’.
cv. ‘Euchlorum’. – A vigorous form with large leaves and fruit; the keys are up to 21⁄2 in. long and nearly 1 in. wide. Leaves dark green. Späth’s nurseries, 1878. There is a fine specimen at East Bergholt Place, Suffolk, measuring 80 × 11 ft (1966).
cv. ‘Leopoldii’. – Leaves stained with yellowish pink and purple. Originated in Belgium about 1860. Other forms of the same character are ‘Simon-Louis Frères’ and ‘Tricolor’.
cv. ‘Prinz Handjery’. – Leaves suffused with yellow above, purple beneath. Very pretty when the leaves are quite young. It is slow-growing and makes a shrubby tree. Späth’s nurseries 1883, or perhaps earlier. ‘Nizetii’ is similar.
var. tomentosum Tausch A. p. var. villosum Parl. – A Variety found in Sicily, S. Italy, and Dalmatia. Leaves covered with down beneath; the margins more coarsely toothed.
f. variegatum (West.) Rehd. – This name is of general application to the common variegated sycamores, with leaves blotched and striped with yellow or yellowish white. Such forms have been known since the early eighteenth century and have even been reported from the wild, but it is doubtful whether they have ever been propagated vegetatively. The plants offered by nurserymen in the later eighteenth and early nineteenth century under such names as “variegatum”, “albo-variegatum”, and “foliis variegatis” were most probably seedlings. The variegation of the leaf seems to have little effect on the vigour of the tree, judging from the many large specimens in the country. At Petersham Lodge, Richmond, there is one of 90 × 121⁄2 ft (1956) and another of about the same height but 161⁄2 ft in girth, at Guisborough Priory, Yorks. (1952). The tallest measured recently is at Linton Park, Kent, 80 × 131⁄2 ft (1965).
cv. ‘Worleei’. – Leaves rich yellow. A superior form of the Corstorphine sycamore, raised in Germany; leaf-stalks reddish.