Commercial Timbers


H. G. Richter and M. J. Dallwitz

Aspidosperma quebracho-blanco Schlecht. (Quebracho blanco)

Nomenclature etc. APOCYNACEAE. Trade and local names: quebracho blanco (PY, AR). Not protected under CITES regulations.

Description based on 3 specimens. Tree. Geographic distribution: tropical South America and temperate South America.

General. Growth ring boundaries distinct. Growth ring limits sometimes indicated by semi porosity and noded rays. Heartwood basically yellow (with a pinkish tinge), without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.85 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, exclusively solitary. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 80–160–240 µm; diameter of vessel lumina: large. Average number of vessels/mm² 10–20; vessels per square millimetre few. Average vessel element length 93–253–434 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, not vestured. Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels not observed.

Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness to very thick-walled. Average fibre length 900–1200 µm. Average fibre length medium. Fibre pits common in both radial and tangential walls, distinctly bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (2–)3–5. Unlignified parenchyma absent.

Rays. Rays present, 8–10 per tangential mm, multiseriate (also if only few), 3–5 cells wide, of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic, located in ray cells. Crystal-containing ray cells procumbent. Crystals in procumbent ray cells in radial alignment. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Silica not observed.

Illustrations. • Transverse section. Aspidosperma quebracho-blanco. • Tangential section. Aspidosperma quebracho-blanco. • Radial section. Aspidosperma quebracho-blanco. • Vessel-ray pits. Aspidosperma quebracho-blanco. Vessel-ray pits typically bordered. • Tracheids. Aspidosperma quebracho-blanco. Note: presence of vasicentric tracheids. • Crystals. Aspidosperma quebracho-blanco. Note: Large prismatic crystals in rays, frequently arranged in radial series (semi-polarised light).

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.’.