Commercial Timbers


H. G. Richter and M. J. Dallwitz

Swintonia spp. (Merpauh)

Nomenclature etc. ANACARDIACEAE. S. floribunda, S. schwenkii. Trade and local names: merpauh (trade); selan (MY-Sar); kaluis, lomarau (PH); civit, taung-thayet (MM); muom (KH, VN). Not protected under CITES regulations.

Tree. Geographic distribution: Burma to Indomalesia.

General. Growth ring boundaries distinct (marked by marginal parenchyma bands). Heartwood basically brown to red, without streaks. Sapwood colour distinct from heartwood colour (greyish brown and often darker than heartwood). Odour indistinct or absent. Density 0.64–0.88 g/cm³. Very high sapwood proportion.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 180–300 µm; diameter of vessel lumina: large to very large. Average number of vessels/mm² 2–8(–10); vessels per square millimetre very few, or few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 10–16 µm, large, not vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular or horizontal to vertical, of uniform size or type. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels not observed.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Average fibre length 700–1000–1400 µm. Average fibre length medium. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal) or not marginal (or seemingly marginal) (additional bands between marginal ones, irregular and often discontinuous), fine, up to three cells wide and coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty to vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–4. Unlignified parenchyma absent.

Rays. Rays present, 5–7 per tangential mm, multiseriate (also if only few), 2(–3) cells wide, narrow (2–3 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular) to 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. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals present, non-traumatic origin, radial type. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells chambered and not chambered. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Silica present and not observed, as grains, in rays cells. In specimens from the northern part of the generic distribution silica regularly present, in specimens from Sumatra very rare or absent.

Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (pale greensih blue); basically colourless to brown or shade of brown. Ethanol extract fluorescent (light blue). 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. Swintonia sp. • Transverse section. Swintonia schwenkii. • Tangential section. Swintonia floribunda. • Radial section1. Swintonia floribunda. Silica particles in rays absent. • Radial section2. Swintonia schwenkii. Silica particles in rays present. • Radial canals. Swintonia schwenkii. Swintonia floribunda. Size of radial intercellular canals variable within the genus Swintonia.

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.’.