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Nomenclature etc. SAPINDACEAE (ACERACEAE). Incl. Acer pseudoplatanus L., A. saccharum L., Acer platanoides L., A. campestre L. Trade and local names: sycamore (GB); maple (US); érable (FR); acero (IT); falso plátano (ES). Not protected under CITES regulations.
Tree. Geographic distribution: Europe, excl. Mediterranean, Mediterranean incl. N. Africa and Middle East, temperate Asia (Acer pseudoplatanus L., Acer platanoides L., A. campestre L.), North America (A. saccharum L.).
General. Growth ring boundaries distinct. Heartwood basically white or grey, brown to yellow, white or grey (generally white to yellowish). Sapwood colour similar to heartwood colour (occasionally dark coloured heartwood present). Density 0.5–0.6–0.7 g/cm³. Wood surface darkens considerably under exposure; special growth patterns: "fiddle back" figure possible in all species, "bird's eye" figure only in A. saccharum.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows. Occasionally small clusters and radial groups of 4. Average tangential vessel diameter 44–65–80 µm. Average number of vessels/mm² 34–38–44. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 8–10 µm. Vessel-ray pits with reduced borders or apparently simple, rounded or angular. Helical thickenings present, in narrow and wide vessel elements, throughout the body of vessel elements. Tyloses absent.
Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 670–880–1080 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres adjacent to vessels with thicker walls.
Axial parenchyma. Axial parenchyma banded. Bands marginal (or seemingly marginal). Bands fine. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 2(–4).
Rays. Rays 6–9–14 per tangential mm, multiseriate, (1–)6–8 cells wide. Rays of two distinct sizes (1–2-seriate and 5–7-seriate), or of one size (in some species). Height of large rays commonly 500 to 1000 µm, or commonly over 1000 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. There is no safe way of differentiating the various species based on microscopic features; within the European species only A. campestre may be separated from other species on account of the fairly narrow rays.
Storied structures. Storied structure absent.
Mineral inclusions. Crystals mostly present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystals observed in many species, i.e., A. campestre and A. rubrum; in some species not, i.e., A. pseudoplatanus. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (light green); colour of water extract colourless to brown. Ethanol extract not fluorescent. Colour of ethanol extract yellow. Froth test positive. Splinter burns to full ash. Ash white to grey.
Illustrations. • Macroscopic images. transverse (ca. 10x). radial (natural size). Acer pseudoplatanus. • Transverse section - European species. Acer platanoides. Acer campestre. • Transverse section - Acer saccharum. Acer saccharum. • Transverse section - enlarged. Acer pennsylvanicum. • Tangential section. Acer platanoides. helical thickenings in vessels. • Radial section. Acer platanoides. homocellular rays, cross-field pits similar to intervascular pits in size and form but with reduced borders ("simple" pits).
The interactive key allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, summaries of attributes within groups of taxa, and geographical distribution.
Cite this publication as: ‘Richter, H.G., and Dallwitz, M.J. 2000 onwards. Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: 9th April 2019. delta-intkey.com’.
