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H. G. Richter and M. J. Dallwitz

Nauclea diderrichii Merrill (Bilinga)

Nomenclature etc. RUBIACEAE. Syn.: N. trillesii Merill, N. badi Aubrév., Sarcocephalus diderrichii De Wild. & Th. Dur., S. trillesii Pierre, S. badi Aubrév., S. xanthoxylon A. Chev. Trade and local names: bilinga (DE, GA, FR, NL, GQ); opepe (NG, GB, BE); badi, sibo, bedo, ekusamba (CI); kusia (GH); akondok, eke, aloma (CM); bonkangu, gulu maza (AO, CD); mokese, kilingi (UG). Not protected under CITES regulations.

Tree. Geographic distribution: tropical Africa.

General. Heartwood basically yellow to red to brown, with streaks (orange-red). Sapwood colour distinct from heartwood colour. Density 0.63–0.7–0.78 g/cm³. Frequently with interlocked and ondulating grain.

Vessels. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern or no specific pattern (often oriented diagonally), exclusively solitary. Average tangential vessel diameter 140–190–240 µm. Average number of vessels/mm² 2–5–12. Perforation plates simple. Intervessel pits restricted to overlapping vessel element tails alternate, average diameter (vertical) 5–6 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits in heartwood vessels present (yellowish brown).

Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness. Average fibre length 1100–1650–2500 µm. Fibre pits common in both radial and tangential walls, distinctly bordered. Fibres septate and non-septate. Fibre pits conspicuously bordered and vestured.

Axial parenchyma. Axial parenchyma apotracheal and paratracheal (paratracheal parenchyma rare). Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (4–)6–8–10.

Rays. Rays (6–)14–18 per tangential mm, multiseriate (also if only few), 1–2–3 cells wide. Rays with multiseriate portions as wide as uniseriate portions present. Rays of one size (could also be interpreted as rays of two size classes if uniseriates are frequent). Rays composed of a single cell type (homocellular) and two or more cell types (heterocellular) (uniseriates often homocellular); homocellular ray cells square or upright. Heterocellular rays with square and upright cells restricted to marginal rows, with more than 4 marginal rows of upright or square cells. Perforated ray cells present, or absent.

Mineral inclusions. Crystals present, prismatic (crystals small in comparison with normal prismatic crystals but larger than those commonly described as microcrstals (crystal sand)) or in form of crystal sand, located in ray cells. Crystal-containing ray cells upright and/or square or procumbent (mostly in upright cells). Silica not observed.

Illustrations. • Macro images. Nauclea diderrichii. Transverse. Radial. • Transverse section. Nauclea diderrichii. • Tangential section. Nauclea diderrichii. • Radial section. Nauclea diderrichii. • Fibre pits. Nauclea diderrichii. Large bordered fibre pits: radial section (left), tangential section (right). Note vestures in pit cavities (Vp). Vp». • Crystals. Nauclea diderrichii. Micro crystals occasionally in square and/or upright ray cells. • Septate fibres. Nauclea diderrichii. Fibres occasionaly septate (Fs). Fs».


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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