Commercial Timbers

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H. G. Richter and M. J. Dallwitz

Castanospermum australe A.Cunn. (Black bean)

Nomenclature etc. FABACEAE-FABOIDEAE. Trade and local names: black bean (AU). Not protected under CITES regulations.

Description based on 4 specimens. Tree. Geographic distribution: Australia.

General. Growth ring boundaries distinct and indistinct or absent. If distinct, growth ring limits demarcated by marginal parenchyma bands. Heartwood basically brown, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.75–0.81 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 80–180–280 µm; diameter of vessel lumina: large and very large. Average number of vessels/mm² 3–6; vessels per square millimetre very few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 7–9 µm, medium, 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 present, brown deposits in vessels.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, banded and not banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Marginal bands rarely distinct. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse. Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–6. Unlignified parenchyma absent. Apotracheal parenchyma: individual strands of chambered, crystalliferous cells.

Rays. Rays present, 8–11 per tangential mm, multiseriate (also if only few), (1–)2–3 cells wide, narrow (2–3 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 two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure present and absent, all rays storied, axial parenchyma not storied, vessel elements not storied, fibres not storied. Arrangement of tiers irregular. Number of ray tiers per axial millimetre 2–3. Rays occasionally with a tendency towards storied arrangement.

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 axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Water extract with orange fluorescence, ethanol extract with purplish fluorescence. Chrome azurol-S test negative. Froth test positive. Splinter burns to partial ash. Ash white to grey.

Illustrations. • Transverse section. Castanospermum australe. • Tangential section. Castanospermum australe. • Radial section. Castanospermum australe.


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. http://delta-intkey.com’.

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