Common Name: Plane Trees
Description: Trees to 30–50 m high, monoecious, deciduous, with leaves, young stems and inflorescences densely dendritic-tomentose; wind-pollinated.
Leaves alternate; petiole swollen at base, enclosing young bud; stipules prominent and leaf-like; lamina simple, palmately lobed or palmatisect; margins often coarsely toothed.
Flowers actinomorphic, borne in dense unisexual globose clusters sessile on elongate axes, small, 3–4 (–8)-merous; perianth in 2 whorls, hypogynous, minute, distinct or basally connate. Male flowers with tiny or vestigial sepals and petals, sometimes with vestigial carpels; stamens as many as and opposite petals, subsessile; anthers opening by lateral slits; connective with a terminal peltate appendage. Female flowers often with 3 or 4 staminodes; petals absent; ovary superior; carpels (3–) 5–8 (–9), free, in 2 or 3 whorls, imperfectly closed, with style terminal and stigma extending onto apex of carpel; ovules 1 (rarely 2) per carpel, pendulous, orthotropous or slightly hemitropous.
Fruits small, hairy achenes or nutlets, borne in globular clusters on elongate axes; seeds with thin testa, scanty endosperm.
Distribution and occurrence: World: c.10 species, native to SE. Europe to Pakistan, Indochina, E. Canada to Guatemala. Australia (naturalised): 1 species WA (naturalised), ACT (doubtfully naturalised).
Generic description as per family description, Platanus is the sole genus in Platanaceae.
Text by K.L. Gibbons 18 Apr. 2023, from A.E. Orchard and B.J. Lepschi (Flora of Australia Online, accessed 17 Apr. 2023) and Heywood et al. 2007 Flowering Plant Families of the World (Kew: Surrey, U.K.).
Taxon concept: fA.E. Orchard and B.J. Lepschi in Flora of Australia Online, [accessed 17 Apr. 2023] and Heywood et al. 2007 Flowering Plant Families of the World (Kew: Surrey, U.K.).
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