Commercial timbers

H. G. Richter and M. J. Dallwitz


Pterygota bequaertii De Wild., P. macrocarpa K. Schum. (Koto)

Nomenclature etc. STERCULIACEAE. Syn.: Sterculia thompsonii Hutch.&Dalz., Pterygota cordifolia A.Chev. Trade and local names: koto(D, CI) akodiakédé, bofo ouale, bontue, pohoure, waré (CI) Pterygota (GB) awari, kyere, wawampe (GH) efok, kion (CAM) kefe, poroporo, oporipo (WAN) aké (G) ikame (ZRE), kakende (RCA.

Tree. Geographic distribution: tropical Africa (other species in Southeast Asia and in tropcal America).

General. Growth ring boundaries distinct. Heartwood basically yellow to white or grey. Sapwood colour similar to heartwood colour. Basic specific gravity 0.46–0.55–0.63 g/cm³.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 95–180–240 µm. Average number of vessels/mm² 1–4. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses in vessels absent. Other deposits in heartwood vessels present.

Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 1265–1785–2780 µm. Fibre pits common in both radial and tangential walls, simple to minutely bordered.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates (sporadically). Paratracheal axial parenchyma scanty and vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (3–)4(–6).

Rays. Rays 3–5 per tangential mm, multiseriate, also if only few, 1–5–7 cells wide. 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. Sheath cells present.

Storied structures. Storied structure present, rays not storied, axial parenchyma storied.

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 and procumbent (less frequent in procumbent cells). Crystals in procumbent ray cells in radial alignment. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one. Silica not observed.

Miscellaneous. • Wood surface. Pterygota sp., radial plane. • Transverse section. Pterygota macrophylla. • Tangential section. Pterygota macrophylla. • Radial section. Pterygota macrophylla.


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).

Index