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Nomenclature etc. MALVACEAE (STERCULIACEAE). Pterocymbium beccari K. Schumann, P. tinctorium (Blanco) Merr., P. tubulatum (Masters) Pierre. Trade and local names: Amberoi (trade); kelumbuk, papita (ID); melembu, teluto, keluak (MY); taluto (PH); sawbya (MM); oi-chang, po-ikeng, po-kradang (TH). Not protected under CITES regulations.
Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Heartwood basically yellow to white or grey. Sapwood colour similar to heartwood colour. Density 0.23–0.4 g/cm³.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows. Average tangential vessel diameter 220–350 µm. Average number of vessels/mm² 1–2(–4). Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses absent.
Tracheids and fibres. Fibres very thin-walled. Average fibre length 1100–2100 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma not banded. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per strand: 2–4. Unlignified parenchyma absent.
Rays. Rays 2–4 per tangential mm (only large rays), multiseriate, 5–12(–20) cells wide. Rays of two distinct sizes. Height of large rays commonly over 1000 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 to mostly 2–4 marginal rows of upright or square cells. Sheath cells present.
Storied structures. Storied structure present, some rays storied, some not, axial parenchyma storied, vessel elements storied, fibres storied. Number of ray tiers per axial millimetre 5–6.
Secretory structures. Oil and mucilage cells absent. Intercellular canals present, traumatic origin (exclusively), oriented axially, axial intercellular canals in short tangential lines.
Mineral inclusions. Crystals present, prismatic and druses, located in ray cells. Crystal-containing ray cells upright and/or square or procumbent (including sheath cells). Number of crystals per cell or chamber one. Silica not observed.
Illustrations. • Transverse section. Pterocymbium beccarii. • Tangential section. Pterocymbium beccarii. • Radial section. Pterocymbium beccarii. • Mineral inclusions. Pterocymbium beccarii. druses (CR) and silica (Si) grains in ray cells. CR. CR. Si. Si.
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’.
