Commercial Timbers


H. G. Richter and M. J. Dallwitz

Aglaia spp. (Bekak, pasak, tasua)

Nomenclature etc. MELIACEAE. Aglaia spp. including the formerly separate genus Amoora. Trade and local names: parak, langsat (ID); bekak, pasak, segera, pak (MY); makaasim, katong (PH); thanatka-wa (MM); chomnay poveang (KH); tasua, sangkhriat (TH). Not protected under CITES regulations.

Tree. Geographic distribution: Burma to Australia.

General. Growth ring boundaries indistinct or absent. Heartwood basically brown to red, without streaks. Sapwood colour distinct from heartwood colour. Odour in some species distinct, or indistinct or absent. Density 0.45–0.9 g/cm³.

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 110–160 µm. Average number of vessels/mm² 8–11. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–4 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Other deposits in heartwood vessels present (light to dark reddish brown).

Tracheids and fibres. Fibres of medium wall thickness to very thick-walled. Average fibre length 1000–1600 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate. Septate fibres evenly distributed.

Axial parenchyma. Axial parenchyma occasionally banded or not banded. Axial parenchyma bands not marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse. Paratracheal axial parenchyma vasicentric, or aliform, or confluent. Aliform parenchyma lozenge, or winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–8.

Rays. Rays 7–11 per tangential mm, multiseriate (also if only few), (1–)2(–3) cells wide. 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 to mostly 2–4 marginal rows of upright or square cells. Some specimens show exclusively uniseriate rays; as this feature is not characteristic for the entire group it is not coded.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered, or not chambered. Number of crystals per cell or chamber one. Silica not observed.

Illustrations. • Transverse section. Aglaia laevigata ("aglaia" type). Aglaia cucullata ("amoora" type). • Tangential section. Aglaia laevigata. Inset: Septate fibres, septae very numerous and in nearly every fibre. • Tangential section. Aglaia cucullata. • Radial section. Aglaia laevigata. Inset: Chambered crystalliferous parenchyma cells. Note: Rays uniformly homocellular. • Radial section. Aglaia cucullata. Note: Rays partly heterocellular.

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.’.