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 (trade); rengas kerbau jalang (MY); rengas tembaga (ID); hekakoro (PG); thayet-thitsi (MM); kroeul (KH); rakban (TH). Not protected under CITES regulations.
Tree. Geographic distribution: Burma to Indomalesia, or Madagascar & other islands.
General. Growth ring boundaries distinct. Heartwood basically brown red, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. 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 arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows or radial rows of 4 or more. Vessel outline rounded. 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, not vestured. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular, unilaterally compound and coarse. Tyloses in vessels present, thinwalled or sclerotic.
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. 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. Fibres non-septate.
Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide or coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–4(–8).
Rays. Rays present, 4–12(–20) per tangential mm, exclusively uniseriate. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. Only rays containing resin canals are multiseriate.
Storied structures. Storied structure absent.
Secretory structures. Oil and mucilage cells absent. Intercellular canals present, non-traumatic origin, radial type. Laticifers or tanniniferous tubes absent.
Cambial variants. Included phloem absent.
Mineral inclusions. Crystals not observed. Silica present, as grains, in rays cells.
Physical and chemical tests. Heartwood extractives leaching out when in contact with water.
Illustrations. • Transverse section. Gluta rengas. • Tangential section. Gluta rengas. Note radial intercellular canals (ICr). ICr. ICr. ICr. • Radial section. ICr. Gluta rengas. Note radial intercellular canal (ICr) and silica particles 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: 25th June 2009. http://delta-intkey.com’.