Heritiera utilis (Sprague) Sprague (Niangón)
Nomenclature etc. STERCULIACEAE. Syn.: Tarrietia utilis. Trade and local names: Niangón (D, CI, GB, WAN), Nyanwen, Wishmore, Angi (D, GB), Kekosi, Kouanda, Yangon (CI), Nyankom, Attabini (GH), Ogoué, Engongkom (G), Yawi (WAL).
Tree. Geographic distribution: tropical Africa.
General. Heartwood basically brown to red (light to dark reddish brown). Sapwood colour distinct from heartwood colour. Basic specific gravity 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 rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 2–4 and more than 4. 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 los radios grandes se extienden sobre 2 a 3 niveles de estratificación.
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.
Cite this publication as: H. G. Richter and M. J. Dallwitz (2000 onwards). 'Commercial timbers: descriptions, illustrations, identification, and information retrieval.' In English, French, German, and Spanish. Version: 4th May 2000. http://biodiversity.uno.edu/delta/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993 onwards, 1995 onwards, 1998) should also be cited (see General references).