Hevea brasiliensis (Willd.) Muell.Arg (Rubberwood)
Nomenclature etc. EUPHORBIACEAE. Trade and local names: Hevea, Hevaru, Rubberwood (GB, D, MAL, T, IN), Gummibaumholz (D), seringa, seringeira (BR), kayu karet (IN), arbol de caucho (SA).
Tree. Geographic distribution: Indomalesia and tropical South America (in Indomalesia cultivated).
General. Growth ring boundaries distinct. Heartwood basically yellow and white or grey. Sapwood colour similar to heartwood colour. Basic specific gravity 0.52–0.6–0.64 g/cm³. With unpleasant odour when fresh.
Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more (rarely up to 10). Average tangential vessel diameter 145–205–260 µm. Average number of vessels/mm² 1–3. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 10–12 µm, vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present (brown).
Tracheids and fibres. Fibres of medium wall thickness. Fibre pits mainly restricted to radial walls, distinctly bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands reticulate, fine, up to three cells wide. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse-in-aggregates (in short tangential lines). Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–8.
Rays. Rays 8–12 per tangential mm, multiseriate, also if only few, 2–5 cells wide. Rays with multiseriate portions as wide as uniseriate portions rarely present, or absent. Rays composed of two or more cell types. Heterocellular rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 2–4, or more than 4.
Storied structures. Storied structure absent.
Cambial variants. Included phloem absent.
Mineral inclusions. Crystals present, prismatic, located in ray cells or axial parenchyma cells. Crystal-containing axial parenchyma cells chambered, or not chambered. Number of crystals per cell or chamber one, or more than one. Crystals in one cell or chamber of the same size, or of two distinct sizes. Silica not observed.
Cite this publication as: H. G. Richter and M. J. Dallwitz (2000 onwards). 'Commercial timbers: descriptions, illustrations, identification, and information retrieval.' In English, French, German, and Spanish. Version: 4th May 2000. http://biodiversity.uno.edu/delta/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993 onwards, 1995 onwards, 1998) should also be cited (see General references).