Commercial Timbers


H. G. Richter and M. J. Dallwitz

Pometia pinnata J.R. Forster & J.G. Forster (Kasai, taun)

Nomenclature etc. SAPINDACEAE. Including Pometia ridleyi King). Trade and local names: kasai, matoa, megan, taun (trade); leungsir, tawan, ihi mendek (ID); sibu (MY-sar); malugai (PH); paga-nyet-su ava (MM); chieng dong, kwaang (LA); sai, daengnam (TH). Not protected under CITES regulations.

Tree. Geographic distribution: Thailand, Laos, Vietnam, Cambodia, or Indomalesia.

General. Growth ring boundaries distinct. Growth ring limits demarcated by marginal parenchyma bands. Heartwood basically brown red, rarely with streaks. Sapwood colour distinct from heartwood colour. Density 0.63–0.7 g/cm³ (PNG). Density very variable (0.39–0.86) as a function of species and origin.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows or radial rows of 4 or more. Average tangential vessel diameter 70–310(–360) µm. Average number of vessels/mm² 1–7. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–4 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings present (rare and inconspicuous). Other deposits in heartwood vessels present (both light coloured and dark brown).

Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 750–1450 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate, or septate and non-septate. Septate fibres evenly distributed.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric, or aliform. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–8.

Rays. Rays 4–12 per tangential mm, exclusively uniseriate. Rays composed of two or more cell types (heterocellular). Heterocellular rays with procumbent, square and upright cells mixed throughout the ray. Some specimens with exclusively uniseriate rays, others also featuring biseriate rays.

Mineral inclusions. Crystals present, prismatic, located in ray cells. Crystal-containing ray cells upright and/or square or procumbent. Number of crystals per cell or chamber one, or more than one. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Froth test positive. Splinter burns to full ash. Ash white to grey.

Illustrations. • Macro images. Transverse. Radial. Pometia pinnata. • Transverse section. Pometia pinnata. • Tangential section. Pometia pinnata. • Radial section. Pometia pinnata. • Ray composition. Pometia pinnata. Close-up uf ray composed of different size cells, some with prismatic crystals.

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.’.