Neotropical Platanaceae

Jon L.R. Every

University of Plymouth, U.K. 

Description

Trees, deciduous. Leaves alternate, simple, lamina palmately lobed, abaxial surface covered in branched hairs, margins dentate, venation tri-nerved; stipules leaf-like; petioles expanded at base, . Inflorescence terminal, pendulous, capitate. Flowers unisexual, monoecious, actinomorphic. Male flowers with 3-4(-7) sepals, free or connate; petals vestigial, alternating with sepals; stamens equal in number to sepals and basally connate; filaments short; anthers dehiscing via longitudinal slits; Female flowers with 3-4(-7) sepals; apetalous; ovary superior, carpels 5-8, free, ovules 1 per carpel, stigmas elongate. Fruit heads of achenes or nutlets, covered in long trichomes. Seeds oily, wind-dispersed.

Notes on delimitation

Distribution in the Neotropics

  • The Platanaceae have their main distribution in temperate North America with an additional one or two species occurring in southeastern Europe and southwestern Asia to Iran. There is also a disjunct species to be found in Indochina (Heywood, 2007). In the Neotropics the genus Platanus L. has a natural southern distribution limit of Guatemala which is enlarged due to its use as a utility tree throughout the Neotropics.

Distinguishing characters (always present)

  • Peeling bark coming off irregularly in large plates.
  • Axillary vegetative buds covered by petiole base.
  • Leaf-like stipules surrounding twig.
  • Flowers condensed into globular heads.
  • Monoecious.
  • Petals minute in male flowers and absent in females.

Number of genera

  • A monogeneric family represented by the genus Platanus L.

Status

  • Two species native to the Neotropics (Platanus mexicana Moric. and P. rzedowskii Nixon & J. M. Poole) with a number of ornamental and commercial species grown throughout both urban and rural areas.

General notes

  • Plane trees.

Important literature

APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society 161(3): 105-121.

Heywood, V.H.H. 2007. Platanaceae. In:  V.H. Heywood, R.K. Brummitt, A. Culham and O. Seberg (eds.). Flowering Plant Families of the World. Pp. 257-258. Royal Botanic Gardens, Kew. 

Mabberley, D.J. 2008. Mabberley's plant book. Third edition. Cambridge University Press, Cambridge.

Nee, M. 2004. Platanaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds.). Flowering Plants of the Neotropics. P 299. The New York Botanical Garden, Princeton University Press, Princeton.

Stevens, P.F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/

Watson, L. and Dallwitz, M.J. (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version 3rd March 2009. http://delta-intkey.com

How to cite

Every, J.L.R. (2010). Neotropical Platanaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Platanaceae.htm.