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Nomenclature etc. DIPTEROCARPACEAE. Syn.: Shorea laevifolia (Parijs) Endert, Hopea laevifolia Parijs. Trade and local names: bangkirai (ID), balau, selangan batu No.1 (trade, MY). Not protected under CITES regulations.
Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Heartwood basically brown to yellow to white or grey, brown to green. Sapwood colour distinct from heartwood colour. Density 0.72–0.85–0.93 g/cm³.
Vessels. Wood diffuse porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows. Average tangential vessel diameter 95–160–225 µm. Average number of vessels/mm² 3–6. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, pits vestured. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits, rounded or angular. Tyloses present (abundant), thinwalled.
Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres very thick-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma banded (axial resin canals in some species present, embedded in parenchyma bands) or not banded. Bands not marginal (or seemingly marginal). Bands fine or coarse. Axial parenchyma paratracheal. Apotracheal axial parenchyma rarely diffuse, or diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric, aliform, confluent, and unilateral. Aliform parenchyma of the winged type. Axial parenchyma as strands. Average number of cells per strand: (2–)4–5.
Rays. Rays 5–8 per tangential mm, multiseriate, 2–3(–4) cells wide. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular), or two or more cell types (heterocellular); homocellular ray cells procumbent. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells.
Storied structures. Storied structure present (not in all specimens), all rays storied or some rays storied, some not, axial parenchyma storied.
Secretory structures. Intercellular canals present, oriented axially, axial intercellular canals in long tangential lines and in short tangential lines.
Mineral inclusions. Crystals present or not observed, prismatic, located in axial parenchyma cells (prismatic crystals sporadically in axial parenchyma cells, however not in all specimens). Crystal-containing axial parenchyma cells chambered and not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size and enlarged (idioblasts). Prismatic crystals sporadically in axial parenchyma cells, however not in all specimens. Silica not observed.
Physical and chemical tests. Colour of water extract yellow. Heartwood extractives leachable when in contact with water (yellow). Splinter burns to charcoal.
Illustrations. • Transverse section. axial intercellular canals (IC) in tangential bands. IC. • Tangential section. • Radial section.
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’.
