Commercial Timbers


H. G. Richter and M. J. Dallwitz

Tetraberlinia bifoliolata, T. tubmaniana (Ekaba)

Nomenclature etc. FABACEAE-CAESALPINIOIDEAE. Syn.: Berlinia bifoliolata Harms. Trade and local names: ekaba (GQ, ES, trade); hoh, sikon, gola (LR); ekop, ekop-ribi (CM); eko-andoung (GH); tetraberlinia (GB). Not protected under CITES regulations.

Tree. Geographic distribution: tropical Africa.

General. Growth ring boundaries distinct or indistinct or absent. Growth ring limits marked by darker latewood zones. Heartwood without streaks. Sapwood colour distinct from heartwood colour. Density 0.52–0.66 g/cm³.

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 150–250 µm. Average number of vessels/mm² 3–6. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits in heartwood vessels occasionally present.

Tracheids and fibres. Fibres very thin-walled, or of medium wall thickness. Average fibre length 700–1700 µm. 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), fine, up to three cells wide or coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric, or aliform. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–8.

Rays. Rays 8–15 per tangential mm, exclusively uniseriate. 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.

Storied structures. Storied structure present, all rays storied, axial parenchyma not storied. Arrangement of tiers irregular. Storied rays only sporadically and in irregular strata in T. tubmanniana.

Secretory structures. Intercellular canals present, traumatic origin, axial type, in long tangential lines or in short tangential lines.

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

Illustrations. • Transverse section. Tetraberlinia tubmaniana. • Tangential section. Tetraberlinia tubmaniana. • Radial section. Tetraberlinia tubmaniana. • Crystals in axial parenchyma. Tetraberlinia bifoliolata.

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.’.