Intsia spp. (Merbau)
Nomenclature etc. CAESALPINIACEAE. I. bijuga (Colebr.) O. Kuntze - Syn.: Macrolobium bijugum Colebr., Afzelia bijuga (Colebr.) A.Gray, I. amboinensis DC., I. retusa (Kurz) Merrill; I. palembanica Miq. - Syn.: Afzelia palembanica Baker, A. bakeri Prain, A. bijuga Kurz, Intsia bakeri Prain. Trade and local names: merbau (MAL); malacca teak, mirabow, Moluccan ironwood (GB); ipil, kayu besi (RI); kwila, bendora (PNG); ipil, ipil laut, malaipil (RP); tat-takun (BUR); krakas prak (K); lumpho, lumpho thale (T); hintzy (RM).
Tree. Geographic distribution: Burma, Thailand, Laos, Vietnam, Cambodia, Indomalesia, Pacific Islands, Australia, and Madagascar & other islands.
General. Growth ring boundaries indistinct or absent. Heartwood basically brown red, without streaks. Sapwood colour distinct from heartwood colour. Basic specific gravity (0.5–)0.69–0.96 g/cm³. As opposed to Afzelia species the yellowish brown extractives in Intsia are water soluble and can be washed out causing nasty stains.
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 120–200–280 µm. Average number of vessels/mm² 2–3(–5). Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (white or yellow and dark reddish brown).
Tracheids and fibres. Fibres of medium wall thickness to very thick-walled. Average fibre length 560–790 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered or distinctly bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform, or confluent. Aliform parenchyma lozenge, or winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2(–4).
Rays. Rays 5–8 per tangential mm, multiseriate, also if only few, (1–)2(–4) cells wide. Rays composed of a single cell type. Homocellular ray cells procumbent.
Storied structures. Storied structure absent.
Secretory structures. Intercellular canals absent.
Cambial variants. Included phloem absent.
Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.
Physical and chemical tests. Heartwood yellow fluorescent. Water extract basically brown yellow or shade of yellow. Heartwood extractives leaching out when in contact with water.
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).