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| Commercial timbers |
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 0.63–0.7–0.8 g/cm³. Frequently with interlocked and ondulating grain.
Vessels. Wood diffuse porous. Vessels arranged in a 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, pits vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits 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 axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: (4–)6–8–10.
Rays. Rays (6–)14–18 per tangential mm, multiseriate, 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). Height of large rays commonly 500 to 1000 µm. 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.
Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent (light violet blue); colour of water extract yellow. Heartwood extractives leachable when in contact with water. Ethanol extract fluorescent (light blue). Colour of ethanol extract yellow. Froth test positive. Splinter burns to charcoal.
Illustrations. • Macroscopic images. transverse (ca. 10x). radial (natural size). • Transverse section. • Tangential section. • Radial section. • Fibre pits. large bordered fibre pits: radial section (left), tangential section (right); note vestures in pit cavities (Vp). Vp». • Crystals. micro crystals (crystal sand) occasionally in square and/or upright ray cells (polatized light). • Septate fibres. 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: 9th April 2019. delta-intkey.com’.
