Sycamore Maple

Acer pseudoplatanus

Summary 5

Acer pseudoplatanus, known as the sycamore in the British Isles and as the sycamore maple in the United States, is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is a large deciduous, broad-leaved tree, tolerant of wind and coastal exposure. It is native to Central Europe and Western Asia, from France eastward to Ukraine, northern Turkey and the Caucasus and southward in the mountains of Italy and northern Iberia.

Description 6

Sycamore trees produce their flowers in hanging branched clusters known as panicles that contain a variety of different flower types. Most are morphologically bisexual, with both male and female organs, but function as if they were unisexual. Some are both morphologically and functionally male, others morphologically bisexual but function as males, and still others are morphologically bisexual but function as females. All of the flower types can produce pollen, but the pollen from functionally female flowers does not germinate. All flowers produce nectar, the functionally female flowers producing it in greater volume and with a higher sugar content.

Sycamore trees are very variable across their wide range and have strategies to prevent self-pollination, which is undesirable because it limits the genetic variation of the progeny and may depress their vigour. Most inflorescences are formed of a mixture of functionally male and functionally female flowers. On any one tree, one or other of these flower types opens first and the other type opens later. Some trees may be male-starters in one year and female-starters in another. The change from one sex to the other may take place on different dates in different parts of the crown, and different trees in any one population may come into bloom over the course of several weeks, so that cross-pollination is encouraged, although self-pollination may not be completely prevented.

The sycamore may hybridise with other species in Acersection Acer, including with A. heldreichii where their natural ranges overlap and with A.velutinum. Intersectional hybrids with A. griseum (Acersection Trifoliata) are also known, in which the basal lobes of the leaf are reduced in size, making the leaves appear almost three-lobed (trifoliate).

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Sources and Credits

  1. (c) Claire O'Neill, some rights reserved (CC BY-NC), uploaded by Claire O'Neill, https://www.inaturalist.org/observations/128486708
  2. (c) Claire O'Neill, some rights reserved (CC BY-NC-ND), uploaded by Claire O'Neill, https://www.inaturalist.org/observations/77335275
  3. (c) Bill MacIndewar, some rights reserved (CC BY-NC), uploaded by Bill MacIndewar, https://www.inaturalist.org/observations/79318284
  4. (c) Claire O'Neill, some rights reserved (CC BY-NC), uploaded by Claire O'Neill, https://www.inaturalist.org/observations/141258074
  5. (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Acer_pseudoplatanus
  6. Adapted by Claire O'Neill from a work by (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Acer_pseudoplatanus
  7. (c) Claire O'Neill, some rights reserved (CC BY-SA)

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