Commercial Timbers


H. G. Richter and M. J. Dallwitz

Guarea spp. (Bossé)

Nomenclature etc. MELIACEAE. G. cedrata (A. Chev.) Pellegr. - Syn: G. alatipetiolata de Wild., Trichilia cedrata A. Chev.; G. laurentii de Wild. - Syn.: Trichilia reygaertii de Wild.; G. thompsonii Sprague & Hutch. Trade and local names: bossé (DE, FR, BE, NL, CD); scented or white guarea (GB, NG); bossé claire (FR); bosasa, lisasa, dumbala (CD); divuiti (GA); bossi, kwabohoro (GH); akuraten, obobonufua (NG); timbi, ebangbembra, obobo (CM); krassé, ibotou, anakué, krassain, m'bossa (CI); G. thompsonii: mutigbanaye (CI); black guarea (NG); bossé foncé (FR); bolon (CM); guarea, diambi (CD). Not protected under CITES regulations.

Tree. Geographic distribution: tropical Africa.

General. Heartwood basically red to brown (G. cedrata: salmon coloured darkening to orange brown) yellow to brown to red (G. thompsonii darkening to copper brown), without streaks. Sapwood colour distinct from heartwood colour. Odour distinct. Density 0.52–0.55–0.65 g/cm³ (G. thompsonii often heavier). Ribbon figure due to interlocked grain; occasionally exudation of coloured extractives.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 85–140–215 µm. Average number of vessels/mm² 7–10–15. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 2–4 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses in vessels absent. Other deposits in heartwood vessels present (dark brown).

Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 800–1300–1550 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate. Septate fibres evenly distributed.

Axial parenchyma. Axial parenchyma banded and not 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 aliform, confluent, and unilateral (predominantly unilateral). Axial parenchyma as strands. Average number of cells per axial parenchyma strand 6–8–10.

Rays. Rays 6–12 per tangential mm, multiseriate (also if only few), (1–)2–3 cells wide. Rays composed of a single cell type (homocellular) and two or more cell types (heterocellular); homocellular ray cells procumbent. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells.

Secretory structures. Intercellular canals 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. Silica present, as grains, in rays cells and in axial parenchyma.

Illustrations. • Macro images. Guarea cedrata. Transverse. Tangential. • Transverse section: G. cedrata. Guarea cedrata. • Tangential section: G. cedrata. Guarea cedrata. • Radial section: G. cedrata. Guarea cedrata. • Silica in rays. Guarea cedrata. • Transverse section: G. thompsonii. Guarea thompsonii. • Tangential section: G. thompsonii. Guarea thompsonii. • Radial section: G. thompsonii. Guarea thompsonii.

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.’.