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Nomenclature etc. DIPTEROCARPACEAE. D. alatus (syn. D. incanus Roxb., D. lemeslei Vesque); D. baudii Korth (syn.: D. duperreana Pierre, D. scortechinii King); D. grandiflorus (Blanco) Blanco (syn.: D. blancoi Blume, D. griffithii Miq., D. motleyanus Hook.f.); D. kerrii King (syn.: D. obconicus Foxw., D. perturbinatus Foxw., D. cuneatus Foxw.); D. costulatus v. Slooten; D. verrucosus Foxw. ex v. Slooten. Trade and local names: yang (FR, TH, VN), gurjun (IN-and, MM, LK), dau (VN, FR), white kanyin, kanyin-byu (MM), chhoeuteal (KH), nhang (LA), keroewing (NL), yang hin, yang na (TH), dzao long (VN). Not protected under CITES regulations.
Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Heartwood basically brown to red, brown to yellow, brown to green; without streaks. Sapwood colour distinct from heartwood colour. Density 0.66–0.75–0.8 g/cm³.
Vessels. Wood diffuse porous. Vessels exclusively solitary. Average tangential vessel diameter 110–210–285 µm. Average number of vessels/mm² 2–3–4. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–7 µm, pits vestured. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular, of uniform size or type and of two distinct sizes or types in the same ray cell, of the same type in adjacent elements and unilaterally compound and coarse. Tyloses present, thinwalled.
Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness. Average fibre length 1600–2100–2500 µm. Fibre pits common in both radial and tangential walls, distinctly bordered.
Axial parenchyma. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse, or diffuse-in-aggregates (connecting short series of resin canals). Paratracheal axial parenchyma scanty and vasicentric. Axial parenchyma as strands. Average number of cells per strand: 4–6.
Rays. Rays 5–9 per tangential mm, multiseriate, (3–)4–6 cells wide. Height of large rays commonly 500 to 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows and procumbent, square and upright cells mixed throughout the ray, mostly 2–4 marginal rows of upright or square cells and with more than 4 marginal rows of upright or square cells. Sheath cells absent.
Storied structures. Storied structure absent.
Secretory structures. Intercellular canals present, oriented axially, axial intercellular canals in short tangential lines or diffusely arranged.
Mineral inclusions. Crystals not observed. Silica present, as grains; in rays cells.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (weakly bluish green in: Dipterocarpus alatus), or not fluorescent (other species); colour of water extract colourless to brown. Ethanol extract fluorescent (weakly bluish green in: Dipterocarpus alatus, D. humeratus; faintly violet in: Dipterocarpus crinitus), or not fluorescent (other species). Colour of ethanol extract colourless to brown. Froth test positive (Dipterocarpus alatus, D. humeratus, D. gracilis), or negative (D. crinitus). Splinter burns to full ash (Dipterocarpus alatus, D. humeratus), or to partial ash (D. gracilis), or to charcoal (D. crinitus). Ash white to grey.
Illustrations. • Macroscopic images: cross section. transverse (ca. 10x). • Macroscopic images: wood surface. surface (natural size). tangential. radial. • Transverse section 1. Dipterocarpus coriaceus. diffuse axial intercellular canals (IC). IC. IC. IC. • Transverse section 2. Dipterocarpus alatus. diffuse axial intercellular canals (IC). IC. IC. IC. IC. IC. • Tangential section. Dipterocarpus coriaceus. • Radial section. Dipterocarpus coriaceus. • Fibre pits; silica. Dipterocarpus coriaceus. large bordered pits in tangential and radial fibre walls. silica grains in ray cells (Si), often embedded in organic contents. Si. Si.
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’.
