Commercial timbers

H. G. Richter and M. J. Dallwitz


Antiaris africana Engl., A. toxicaria Lesch., A. welwitschii Engl. (Ako)

Nomenclature etc. MORACEAE. Trade and local names: Afrika: ako (D, CI, SN), antiaris (D, GB), akede (CI), bonkonko (ZRE), chenchen (GH), kirundu (EAfr), mongodou, false oro (WAN), vawi, diolosso (CAM); Asien: ipoh, opas. Status of protection under CITES regulations: not protected.

Tree. Geographic distribution: Burma (only A. toxicaria), or Thailand, Laos, Vietnam, Cambodia (only A. toxicaria), or Indomalesia (only A. toxicaria), or tropical Africa.

General. Growth ring boundaries indistinct or absent, growthring limits macroscopically evident from lower vessel frequency and dark coloured latewood (thick-walled fibres). Heartwood basically yellow to white or grey brown to yellow. Sapwood colour similar to heartwood colour. Basic specific gravity 0.4–0.45–0.5 g/cm³. Ribbon figure due to interlocked grain.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Occasionally radial vessel groups of 4 and small clusters. Average tangential vessel diameter 155–200–245 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 9 µm. Vessel-ray pits with reduced borders or apparently simple, rounded or angular to horizontal to vertical, of uniform size or type, of the same type in adjacent elements. Tyloses in vessels present, thinwalled. Vessel lines on longitudinal surfaces often appearing dark due to blue stain.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled to of medium wall thickness (the latter quite rare). Average fibre length 640–1050–1375 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate. Septate fibres evenly distributed.

Axial parenchyma. Axial parenchyma present. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric to aliform (less frequently aliform and confluent). Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4(–8). Vasicentric parenchyma not clearly distinct from fibres.

Rays. Rays multiseriate, also if only few, (1–)3–6 cells wide. 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 1 to 2–4.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals present, radial type. Latex tubes.

Mineral inclusions. Crystals present, prismatic and in other forms (small, mostly circular crytals), located in ray cells, axial parenchyma cells, and fibres (the latter reported only for A. toxicaria by Janssonius). Crystal-containing ray cells upright and/or square and procumbent. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one, or more than one. Crystals in one cell or chamber of the same size, or of two distinct sizes. Silica not observed.

Miscellaneous. • Transverse section. Antiaris africana. • Tangential section. Antiaris africana. • Radial section. Antiaris africana.


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