Commercial Timbers


H. G. Richter and M. J. Dallwitz

Sterculia apetala (Jacq.) Karst. (Mahot blanc, cacao de monte)

Nomenclature etc. STERCULIACEAE. Trade and local names: chicha, camoruco. Not protected under CITES regulations.

Description based on 6 specimens. Tree. Geographic distribution: Mexico and Central America and tropical South America.

General. Heartwood basically brown red (mostly light brown). Sapwood colour similar to heartwood colour. Density 0.34–0.53 g/cm³.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 128–267 µm. Average number of vessels/mm² 2–4. Average vessel element length 248–493 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 8 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses in vessels present.

Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 1833–2405 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (1–)4.

Rays. Rays 2 per tangential mm, multiseriate (also if only few), 6–15 cells wide. 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. Sheath cells present (with crystals).

Storied structures. Storied structure present, axial parenchyma storied, vessel elements storied.

Secretory structures. Intercellular canals present, traumatic origin, axial type.

Mineral inclusions. Crystals present, prismatic, located in ray cells or axial parenchyma cells. Crystal-containing ray cells upright and/or square (in sheath cells). Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically yellow or shade of yellow. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown or shade of brown.

Illustrations. • Transverse section. Sterculia apetala. • Tangential section. Sterculia apetala. • Radial section. Sterculia apetala.

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.’.