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| Commercial timbers |
Nomenclature etc. BURSERACEAE. Trade and local names: gaboon, gabun (DE), angouma, okaka (GA), angum , ongoumi, moukoumi, zonga (GQ). Not protected under CITES regulations.
Tree. Geographic distribution: tropical Africa.
General. Heartwood basically brown, red (pink brown). Sapwood colour similar to heartwood colour, or distinct from heartwood colour. Density 0.31–0.41–0.54 g/cm³.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows. Average tangential vessel diameter 90–160–210 µm. Average number of vessels/mm² 2–10–25. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 9–11 µm. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular or horizontal to vertical, of uniform size or type. Tyloses present, thinwalled.
Tracheids and fibres. Fibres very thin-walled, or of medium wall thickness. Average fibre length 635–1110–1810 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate; evenly distributed.
Axial parenchyma. Axial parenchyma present. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 5–9.
Rays. Rays 5–9 per tangential mm, multiseriate, 2–3 cells wide. Height of large rays up to 500 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 or mostly 2–4 marginal rows of upright or square cells.
Storied structures. Storied structure present or absent, all rays storied. Arrangement of tiers irregular (storied arrangement (of rays) only irregular).
Secretory structures. Oil and mucilage cells absent. Intercellular canals absent.
Mineral inclusions. Crystals present (infrequent), prismatic, located in ray cells. Crystal-containing ray cells upright and/or square. Number of crystals per cell or chamber more than one. Crystals in one cell or chamber of two distinct sizes. Silica present, as grains; in rays cells.
Illustrations. • Transverse section. • Tangential section. • Radial section. • Silica. silica grains in ray cells.
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’.
