A deciduous tree over 100 ft high in a wild state, with a trunk 9 to 12 ft in girth, forming a shapely rounded head of branches; branchlets glabrous. Leaves palmate, usually five-lobed, heart-shaped at the base, 4 to 6 in. wide; always downy in the axils of the chief veins beneath, but varying in different trees from glabrous to downy in other parts. Flowers without petals, greenish yellow, produced in clusters, each flower on a thread-like, hairy stalk more than 2 in. long. Fruit glabrous, wings 1 in. long, 3⁄8 in. wide.
Native of eastern N. America; introduced, according to Aiton, in 1735, but not many fine specimens are to be found in this country. The most notable arc in the Westonbirt collection, the finest there, and perhaps in the country, being in the Park, near the lodge, measuring 80 × 8 ft (1966). Others at Westonbirt are: Willesley Drive 70 × 43⁄4 ft; Circular Drive 63 × 53⁄4 and 65 × 43⁄4 ft (1966). In the grounds of Blenheim Palace, Oxon., there is a tree of 64 × 51⁄4 ft (1965). In Ireland the best recorded is at Mount Usher, Co. Wicklow, Eire, 62 × 71⁄4 ft (1966). In leaf, the sugar maple, especially in its more glabrous form, bears some resemblance to the Norway maple; but the sap of the sugar maple is watery, not milky as in the other.
The famous maple sugar of N. America is obtained almost solely from the sap of this tree. The State of Massachusetts alone used to supply more than half a million pounds annually. It is obtained by tapping the trees and collecting the juice, which is afterwards evaporated. As an ornamental tree in England this maple never seems to have been a great success, and although it appears to be quite hardy, does not grow quickly when young. In streets, and isolated in the meadows of New England, it is magnificent, and forms one of the chief elements in the glorious colour effects of autumn there, its leaves dying off into various shades of orange, gold, scarlet, and crimson, each tree, according to Emerson, retaining year after year its particular shades.
var. rugelii (Pax) Rehd. A. rugelii Pax – A large tree with thin, three-lobed leaves; the lobes usually entire, triangular, pointed; lower surface rather glaucous and downy. Found wild from N. Carolina and Georgia to Missouri, being the common form of sugar maple in that region. The lower branches often bear leaves identical with those of the type. Introduced to Kew in 1908.
cv. ‘Temple’s Upright’. – A very striking form with a narrow columnar habit. Once known as A. saccharum monumentale.
A. barbatum Michx. – This species, known as the southern sugar maple, takes the place of A. saccharum in the coastal plain, from Virginia to Texas. It makes a smaller tree with a paler bark; leaves smaller, to 3 in. wide, usually downy beneath; lobes with entire or undulate margins. The name A. floridanum Pax has also been used for this species. It is in cultivation at the Glasnevin Botanic Garden, where there is a tree 25 ft high.
A. nigrum Michx. f. A. saccharum var. nigrum (Michx. f.) Britt. – Another close ally of the sugar maple, known as the black maple, and found growing with it in the northern states of eastern and central U.S.A. The marks of distinction are the darker, more furrowed bark, the darker and duller green leaves with rather drooping sides, and the shallower, more rounded toothing of the lobes. According to Sargent it may be distinguished at all seasons by the orange colour of the branchlets.
A. leucoderme Small A. saccharum var. leucoderme (Small) Sarg. – A small shrubby tree, rarely more than 25 ft high, with a pale grey or chalky white bark. It is closely allied to the sugar maple but comes from further south, being commonest, according to Sargent, in the more northern parts of Georgia and Alabama. Leaves three- or five-lobed, 2 to 31⁄2 in. long and wide, the lobes triangular, with usually two large teeth; the base truncate or slightly heart-shaped; lower surface covered with whitish velvety down, especially where the five veins meet the leaf-stalk, which is glabrous. Introduced to Kew in 1902, when seed was received from Prof. Sargent. The specimen now in the collection measures 28 × 13⁄4 ft (1960). There is one at Westonbirt, Glos., measuring 51 × 23⁄4 ft (1967).