plane tree, sycamore, or buttonwood, any species of the genus Platanus, deciduous trees of most temperate regions of the Northern Hemisphere, exclusive of Africa. The hairy, dry, seedlike fruits are densely packed into a hard brown ball, hence the name buttonwood. The large American sycamore, or plane (P. occidentalis), supplies a hardwood popular for carpentry, furniture, and butchers' blocks. The Oriental plane (P. orientalis) of the Mediterranean area and W Asia is used for wood pulp. The London plane (P. acerifolia), sometimes miscalled Oriental plane, is much planted as an ornamental shade tree in cities; it is probably a hybrid of the American and Oriental planes. Sycamore is sometimes spelled sycomore, but should not be confused with the unrelated sycomore fig (Ficus sycomorus) of the family Moraceae. Plane trees are classified in the division Magnoliophyta, class Magnoliopsida, order Hamamelidales, family Platanaceae.

Any of ten species of large trees that make up the genus Platanus, sole genus of the family Platanaceae, native to North America, eastern Europe, and Asia. Plane trees are planted widely in cities for their resistance to diseases and to air pollution and because they grow rapidly and furnish quick shade. They are characterized by scaling bark; large, deciduous, usually lobed leaves; and globular heads of flower and seed. Ball-shaped smooth or bristly seed clusters, which dangle singly and often persist after leaf fall, are key identifiers. Winter bark is patchy and picturesque; as the outer bark flakes off, inner bark shows shades of white, gray, green, and yellow.

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