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| Commercial timbers |
Nomenclature etc. ANACARDIACEAE. Important species: Gluta curtisii, G. papuana, G. renghas, G. wallichii; timbers of the genus Melanochyla are also traded as 'rengas'. Trade and local names: rengas kerbau jalang (MY); rengas tembaga (ID); hekakoro (PG); thayet-thitsi (MM); kroeul (KH); rakban (TH). Not protected under CITES regulations.
Tree. Geographic distribution: Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia, Madagascar & other islands.
General. Growth ring boundaries distinct. Heartwood basically brown, red; with streaks. Sapwood colour distinct from heartwood colour. Density 0.57–0.8 g/cm³. Colour of heartwood variable: in some species uniformly greyish brown, in others deep reddish brown with black streaks.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more. Average tangential vessel diameter 115–260 µm. Average number of vessels/mm² 2–6. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 9–12 µm. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular, unilaterally compound and coarse. Tyloses present, thinwalled or sclerotic.
Tracheids and fibres. Fibres of medium wall thickness to very thick-walled. Average fibre length 600–1200 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma present, banded. Bands marginal (or seemingly marginal). Bands fine or coarse. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per strand: 3–4(–8).
Rays. Rays 4–12(–20) per tangential mm, exclusively uniseriate. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. Only rays containing resin canals are multiseriate.
Secretory structures. Intercellular canals present, oriented radially. Laticifers or tanniniferous tubes absent.
Mineral inclusions. Crystals not observed. Silica present, as grains; in rays cells.
Physical and chemical tests. Heartwood extractives leachable when in contact with water.
Illustrations. • Transverse section. Gluta rengas. • Tangential section. Gluta rengas. radial intercellular canals (IC). IC. IC. IC. • Radial section. IC. Gluta rengas. radial intercellular canal (IC) and silica grains in ray cells.
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’.
