Commercial Timbers


H. G. Richter and M. J. Dallwitz

Piptadeniastrum africanum (Hook.f.) Brenan (Dabema)

Nomenclature etc. FABACEAE-MIMOSOIDEAE. Syn.: Piptadenia africana Hook.f. Trade and local names: dabema, dahoma (trade); mbele, mbeli, guli (LR); dabema (CI); dahoma (GH); agboin, ekhimi (NG); atui (CM); tom (GQ); toum (GA); n'singa (AO, CG); bokungu, likundu (CD). Not protected under CITES regulations.

Description based on 8 specimens. Tree. Geographic distribution: tropical Africa.

General. Growth ring boundaries indistinct or absent. Heartwood basically brown, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.6–0.74 g/cm³. Green wood with very bad odour.

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 150–250–330 µm. Average number of vessels/mm² 2–6. Average vessel element length 240–280–300 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–8 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (yellowish brown).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Average fibre length 1150–2340 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres septate and non-septate, or non-septate. Septate fibres evenly distributed, or scattered near vessels and rays.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide or coarse, more than three cells wide. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse (individual, mostly crytalliferous strands). Paratracheal axial parenchyma vasicentric, aliform, and confluent. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–6.

Rays. Rays 4–7 per tangential mm, multiseriate (also if only few), (2–)3–5 cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

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

Illustrations. • Transverse section. Piptadeniastrum africanum. • Tangential section. Piptadeniastrum africanum. • Radial section. Piptadeniastrum africanum.

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.’.