Nomenclature etc. STERCULIACEAE. Syn.: Tarrietia utilis. Trade and local names: Niangón (DE, CI, GB, NG), nyanwen, wishmore, angi (DE, GB), kekosi, kouanda, yangon (CI), nyankom, attabini (GH), ogoué, engongkom (GA), yawi (LR). Not protected under CITES regulations.
Tree. Geographic distribution: tropical Africa.
General. Heartwood basically brown to red (light to dark reddish brown). Sapwood colour distinct from heartwood colour. Density 0.6–0.65 g/cm³. Surface sticky due to rubber-like compounds.
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 200–260–320 µm. Average number of vessels/mm² 3. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits in heartwood vessels present (dark reddish brown).
Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 500–1100–2050 µm. Fibre pits common in both radial and tangential walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma banded or not banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide or coarse, more than three cells wide. Marginal parenchyma bands not always present. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4.
Rays. Rays 3–6 per tangential mm, multiseriate (also if only few), 3–8 cells wide. Rays of two distinct sizes. Height of large rays commonly over 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 2–4 marginal rows of upright or square cells and with more than 4 marginal rows of upright or square cells. Sheath cells present.
Storied structures. Storied structure present, some rays storied, some not, axial parenchyma storied, vessel elements storied, fibres storied. Arrangement of tiers regular (horizontal or straight). Largest rays extend over 2 to 3 stories.
Secretory structures. Intercellular canals absent.
Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells chambered. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.
Illustrations. • Macro images. Heritiera utilis. Transverse. Radial. • Transverse section. Heritiera utilis. • Tangential section. Heritiera utilis. • Radial section. Heritiera utilis.
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’.