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Nomenclature etc. THYMELAEACEAE. Important species: Aquilaria crassna Pierre ex Lecomte. A. malaccensis Lam. (syn. A. agallocha Roxb.). Trade and local names: Trâm huong, dó bâu (VN); aloewood, agarwood (GB, US); bois d'aigle, bois d'aloès (FR); karas, kayu garu (MY); gaharu mengkaras (MY-SWK); akyau (MM); tanduk, udúr (IN); kaju alim, kaju gaharu (ID); Chan krasna (KH); tengala (BN). Listed in CITES Annex II.
Description based on 4 specimens. Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Heartwood basically yellow. Sapwood colour similar to heartwood colour. Odour distinct (nur die harzgetränkten Stücke traumatischen Ursprungs only the resin impregnated chunks of traumatic origin), or indistinct or absent. Density 0.33–0.4 g/cm³. Wood normal wood of no commercial potential.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more or in clusters (few). Average tangential vessel diameter (60–)80–110–145(–200) µm; diameter of vessels: small to medium. Average number of vessels/mm² 9–15; vessels per square millimetre very few to few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) (3–)4–6 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits present.
Tracheids and fibres. Fibres very thin-walled to of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered or distinctly bordered (in some specimens).
Axial parenchyma. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 2.
Rays. Rays 5–8 per tangential mm, exclusively uniseriate (few with a biseriate central portion). Height of large rays up to 500 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells.
Cambial variants. Included phloem present, diffuse.
Mineral inclusions. Crystals not observed. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Colour of water extract colourless to brown.
Illustrations. • Macroscopic images. the normal wood is not traded, only the resin impregnated chunks ("nuggets") of traumatic origin (see above) enter commerce in different sizes and grades; this material is a much sought after source of incense and fetches high prices in the international market. Transverse section, ca. 10x. Grade 1. Grade 2. Grade 3. ungraded. • Transverse section 1. Aquilaria malaccensis. fully developed phloem islands of a mature tree. • Transverse section, blow-up. Aquilaria crassna. phloem islands in an early stage of development in a young tree. • Tangential section. Aquilaria malaccensis. • Radial section. Aquilaria malaccensis.
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’.
