Trees deciduous (rarely semi-evergreen), monoecious. Branches and leaves with branched or stellate tomentum; bark pale brown, gray, and/or white, smooth, exfoliating in plates. Terminal buds absent; lateral buds ovoid, slightly acute at apex, enclosed by a separate scale at base of petiole. Leaves alternate; stipules basally surrounding stem, deciduous; petiole long, usually enclosing axillary bud at base; leaf blade simple, large, usually palmately lobed and subpalmately veined, margin coarsely dentate. Flowering branchlets leafy only at base, pendulous at least in fruit; inflorescences 1–5(–12), globose-capitate, male and female ones homomorphic, borne on separate branchlets. Male flowers: sepals 3–8, triangular, pubescent; petals as many as sepals, oblanceolate; stamens 3–8; filaments short; anther connective enlarging into a peltate scale. Female flowers: carpels 3–8, free; ovary long ovoid, 1-locular; ovules 1 or 2, anatropous; style elongate, persistent and exserted from inflorescence. Infructescence a capitate or globose coenocarpium composed of numerous achenes. Achenes narrow and long obconical, 1-seeded, base usually with a tuft of villous hairs, apex with persistent style; style and hairs often exserted from infructescence. Seeds linear; endosperm thin; cotyledons heteromorphic.
One genus and 8–11 species: Central and North America, SW Asia, SE Europe, one species in SE Asia (Laos and N Vietnam); widely cultivated elsewhere; three species (introduced) in China.
Hoot et al. (Ann. Missouri Bot. Gard. 86: 1–32. 1999) treated Platanaceae and Proteaceae as well-supported sister taxa forming a less well supported clade with Nelumbonaceae.
Chang Hung-ta. 1979. Platanaceae. In: Chang Hung-ta, ed., Fl. Reipubl. Popularis Sin. 35(2): 118–121.