Sycamore Tree Identification: Bark, Leaves, Seed Balls

The word names two unrelated trees. In North America, sycamore means the American sycamore (Platanus occidentalis), a plane tree with peeling white bark and hanging seed balls. In Britain and Ireland, sycamore means Acer pseudoplatanus, a maple with winged helicopter seeds. The Woodland Trust describes the British tree; the Missouri Department of Conservation and the University of Nebraska describe the American one.

One check separates them at any time of year: look at how the leaves or buds sit on the twig. The Missouri Department of Conservation describes American sycamore leaves as alternate, one per node, staggered along the twig. Maples, including the UK sycamore, have opposite leaves in pairs; MDC gives the same arrangement for sugar maple. Seeds settle it in autumn: balls mean Platanus, winged pairs mean a maple.

No other large eastern tree has bark like it. The Missouri Department of Conservation describes the bark as smooth and greenish on young trunks, turning reddish-brown to gray, and shedding in thin plates to reveal white new bark. Davey Tree describes the result as a mottled trunk of greenish-white and brown, with white patches becoming more prominent as the tree ages.

Confirming features:

• Leaves: MDC gives 4 to 8 inches long and broad or larger, with 3 to 5 broad, shallow lobes and coarse teeth; bright green above, whitish and hairy beneath. The University of Nebraska describes the leaves as lobed like a maple's.
• Buds: MDC notes the buds are entirely enclosed by the base of the leaf stalk. Pull a leaf off in summer and the bud is sitting inside the hollow base of the stalk.
• Seed balls: spherical, 1 to 1.5 inches wide, drooping on a stalk 3 to 6 inches long and persisting through winter (MDC).
• Twigs: slender, shiny and zigzag (MDC).

MDC gives heights up to 120 feet; Davey Tree gives a typical 100 feet, occasionally 150, with growth of about 2 feet a year.

The Woodland Trust describes the British sycamore as a large maple with:

• Leaves palmate with five lobes, 7 to 16 cm across, veins hairy on the underside; young trees often have red leaf stalks
• Bark dark pink-grey and smooth when young, becoming cracked and forming small plates with age
• Flowers small and green-yellow, hanging in spikes
• Seeds two-winged helicopters joined at a narrower V-shaped angle than those of similar maples
• Twigs pink-brown and hairless, useful in winter

It can reach 35 m and typically lives 200 to 400 years. The Woodland Trust notes it is not native to Britain: it was introduced either by the Romans or in the Tudor period, planted widely in the 1700s and recorded as naturalised from the mid-1800s. Its two common look-alikes are Norway maple and field maple; the narrow angle between the seed wings is the Woodland Trust's quickest separating feature.

The Missouri Department of Conservation lists sweet gum, sugar, red and silver maples, cottonwood and tulip tree as species similar to American sycamore. The checks that separate the ones people ask about most:

• Maple: opposite leaves and paired winged seeds (MDC gives sugar maple leaves as opposite, with samaras usually in pairs). Sycamore is alternate, with a seed ball.
• Eastern cottonwood: MDC describes broadly triangular leaves 3 to 7 inches long on a flattened leaf stalk, and mature bark that is thick and corky with deep straight grooves. Its seeds carry tufts of cotton. Both grow along rivers, but cottonwood leaves are not lobed and its old bark never flakes to white.
• American beech: MDC describes unlobed, coarsely toothed leaves 3 to 6 inches long and smooth, light- to steel-gray bark that does not peel, plus long cigar-shaped winter buds 3/4 to 1 inch long. Both trees can look pale-barked from a distance; up close, beech bark is uniform gray and sycamore bark is patchwork.

The plane-tree genus Platanus contains about a dozen named species, though not all are accepted by every authority, according to Wikipedia's summary of the genus. The ones most people meet:

• American sycamore (Platanus occidentalis): the United States and Canada
• California sycamore (P. racemosa) and Arizona sycamore (P. wrightii): the Southwest
• Oriental plane (P. orientalis): Eurasia
• London plane (P. × hispanica): a hybrid of American sycamore and Oriental plane, planted on city streets worldwide

London plane is the one that causes confusion in cities. The number of seed balls on each stalk is a helpful clue: American sycamore carries 1 to 2, London plane 1 to 4 or more. Davey Tree describes London plane bark as brownish-gray and cream rather than bright white.

Size and wildlife value. The Missouri Department of Conservation notes that sycamore seeds feed finches, hollow trunks shelter mammals, chimney swifts and swallows, and great blue herons and bald eagles often nest in sycamores. The wood has been used for crates, furniture, butcher blocks and buttons, which is where the old name buttonwood comes from.

NatureLens gives free scans every day, so you can photograph the plant or sign and get a suggested name in seconds, then confirm it with the checks on this page.