Commercial Timbers

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H. G. Richter and M. J. Dallwitz

Pentace spp. (Melunak)

Nomenclature etc. TILIACEAE. Pentace adenophera Kosterm., P. bracteolata ?, P. curtisii King, P. laxiflora Merr., P. macrophylla ?, P. triptera Mast., Pentace spp. Trade and local names: melunak, balong ayan, baru, pinang, sisiat, takalis, tassiet (ID, MY). Not protected under CITES regulations.

Tree. Geographic distribution: Burma, Thailand, Laos, Vietnam, Cambodia, and Indomalesia.

General. Heartwood basically brown to red. Sapwood colour distinct from heartwood colour. Density 0.42–0.59–0.73 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 100–150–210 µm. Average number of vessels/mm² 6–14. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–4(–5) µm. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits, horizontal to vertical, unilaterally compound and coarse. Helical thickenings absent. Tyloses in vessels present, thinwalled.

Tracheids and fibres. Fibres of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma not banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma scanty and vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–6.

Rays. Rays 6–8 per tangential mm, multiseriate (also if only few), 2–4 cells wide. Rays composed of a single cell type (homocellular), or two or more cell types (heterocellular) (only weakly heterocelular); homocellular ray cells procumbent. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells. Tile cells absent.

Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied. Number of ray tiers per axial millimetre 2, or 3.

Secretory structures. Intercellular canals absent.

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

Illustrations. • Transverse section. Pentace triptera. • Tangential section. Pentace triptera. • Radial section. Pentace triptera. • Ray-vessel pitting. Pentace triptera.


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. http://delta-intkey.com’.

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