Commercial Timbers


H. G. Richter and M. J. Dallwitz

Eribroma oblonga (Mast.) Bodard (Eyong)

Nomenclature etc. STERCULIACEAE. Syn.: Sterculia oblonga Mast. Trade and local names: Yellow Sterculia, white Sterculia (GB, NG); azodo, bi (CI); njong (GA); n'chong (GQ); bongele, ekonge, lom, moan (CM); ebenebe, kokoniko, okoko, orodo (NG); bongo (CD). Not protected under CITES regulations.

Description based on 8. Tree. Geographic distribution: tropical Africa (West-).

General. Growth ring boundaries indistinct or absent. Heartwood basically cream coloured to yellow. Sapwood colour similar to heartwood colour. Density 0.7–0.8 g/cm³. Wood of commercial potential.

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter (100–)210(–270) µm; diameter of vessel lumina: large to very large. Average number of vessels/mm² 2–7; vessels per square millimetre very few, or few. Average vessel element length 400–500 µm. Average vessel element length medium. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, small. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses in vessels absent. Other deposits in heartwood vessels present (honey to amber coloured color de miel o ámbar).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness to very thick-walled. Average fibre length (1600–)1970(–2250) µm. Average fibre length long. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands bands much wider than rays, coarse, more than three cells wide (up to 15 cells). Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform, or confluent. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–5.

Rays. Rays 2–4 per tangential mm, multiseriate (also if only few), 3–15 cells wide, of medium width (3–5 seriate) to very wide (more than 10 seriate). Height of large rays commonly 500 to 1000 µm, or 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. Sheath cells present.

Storied structures. Storied structure present, rays not storied, axial parenchyma storied, vessel elements storied, fibres storied. Arrangement of tiers regular (horizontal or straight). Number of ray tiers per axial millimetre 2–3.

Secretory structures. Intercellular canals present, traumatic origin (exclusively), axial type, in short tangential lines.

Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square (in sheath cells). Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. The cristalliferous chambered parenchyma strands are few and relatively short in the inner regios of the bands whereas those adjacent to the fibrous tissue can be very long and numerous.. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative. Splinter burns to full ash, or to partial ash. Ash white to grey.

Illustrations. • Transverse section. Eribroma oblonga. • Tangential section. Eribroma oblonga. • Radial section. Eribroma oblonga. Note chains of crystalliferous chambered parenchyma cells (blowup left) along the parenchyma-fibre interface. • Traumatic canals. Eribroma oblonga. Traumatic intercellular (resin) canals (TRC). TRC.

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.’.