Parashorea spp. (Urat mata, white seraya, gerutu)
Nomenclature etc. DIPTEROCARPACEAE. Leichte Hölzer: Parashorea macrophylla, P. malaanonan, P. tomentella; schwere Hölzer: P. aptera, P. densiflora, P. lucida, P. parviflora, P. smythiesii, P. stellata. Trade and local names: Leichte Hölzer: light weight timbers: heavy timbers: comment: this timber group is not to be mixed up with the trade timber 'white meranti' (Shorea/anthoshorea).
Tree. Geographic distribution: Burma, Thailand, Laos, Vietnam, Cambodia, and Indomalesia.
General. Heartwood basically white or grey and brown (light-weight timbers light brown with pinkish hue) green and brown (heavy timbers olive brown), heavy timbers only with streaks. Sapwood colour similar to heartwood colour, or distinct from heartwood colour. Basic specific gravity 0.35–0.63 g/cm³ (light-weight timbers), or 0.6–0.8 g/cm³ (heavy timbers).
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 180–280 µm. Average number of vessels/mm² 3–7. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm, vestured. Vessel-ray pits with distinct borders or with reduced borders or apparently simple, similar to intervessel pits or different from intervessel pits, rounded or angular (round to oval). Tyloses in vessels present, thinwalled.
Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness. Fibre pits common in both radial and tangential walls, distinctly bordered.
Axial parenchyma. Axial parenchyma rare apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric, aliform, confluent, and unilateral paratracheal. Aliform parenchyma winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4.
Rays. Rays 4–6 per tangential mm, multiseriate, also if only few, (2–)4–7 cells wide. 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 1, or 2–4. Sheath cells only Parashorea lucida present.
Storied structures. Storied structure present, axial parenchyma storied.
Secretory structures. Intercellular canals present, axial type or radial type (only P. smythiesii), in long tangential lines or in short tangential lines.
Mineral inclusions. Crystals present, prismatic, located in ray cells or axial parenchyma cells. Crystal-containing ray cells procumbent, upright and/or square ray cells chambered or not chambered. Crystals in procumbent ray cells in radial alignment. Crystal-containing axial parenchyma cells chambered, or not chambered. Number of crystals per cell or chamber one, or more than one. 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).