PLATANACEAE - - Plane-tree Family

Platanus ×acerifolia Willdenow [occidentalis×orientalis] — London Planetree

London Planetree (Platanus ×acerifolia) - is a hybrid of Platanus orientalis (Oriental Plane) and Platanus occidentalis (American sycamore). The London Plane is a large deciduous tree growing 20–30 m (65–100 ft), exceptionally over 40 m (130 ft) tall, with a trunk up to 3 m (10 ft) or more in circumference. The bark is usually pale grey-green, smooth and exfoliating, or buff-brown and not exfoliating. The leaves are thick and stiff-textured, broad, palmately lobed, superficially maple-like, the leaf blade 10–20 cm (4–8 in) long and 12–25 cm (5–10 in) broad, with a petiole 3–10 cm (1–4 in) long. The flowers are borne in one to three (most often two) dense spherical inflorescences on a pendulous stem (American Sycamore has only 1), with male and female flowers on separate stems. The fruit matures in about 6 months, to 2–3 centimetres (0.8–1.2 in) diameter, and comprises a dense spherical cluster of achenes with numerous stiff hairs which aid wind dispersal; the cluster breaks up slowly over the winter to release the numerous 2–3 mm (0.08–0.12 in) seeds.

Habitat:

Disturbed areas; hybrid of our native species and the Eurasian P. orientalis, planted as a street tree and reported as “occasionally escaping."

Habitat information from:
Weakley, Alan S., Flora of the Southern and Mid-Atlantic States, Working Draft of 21 May 2015.

The range of Platanus ×acerifolia (London Plane-tree)

Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].