Commercial Timbers


H. G. Richter and M. J. Dallwitz

Platymiscium pinnatum (Jacq.) Dugand (Cristobal, macacaúba)

Nomenclature etc. FABACEAE-FABOIDEAE. Trade and local names: cristobal (CR); granadillo (MX); hormigón (GT); macacaúba, macawood (BR); roble (VE). Not protected under CITES regulations.

Description based on 5 specimens. Tree. Geographic distribution: Mexico and Central America and tropical South America.

General. Heartwood basically red (bright red to reddish or purplish brown), without streaks. Sapwood colour similar to heartwood colour, or distinct from heartwood colour (sapwood white). Density 0.75–0.9 g/cm³.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 60–180 µm. Average number of vessels/mm² 4–12. Average vessel element length 150–410 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–10 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits in heartwood vessels present (yellowish).

Tracheids and fibres. Fibres very thick-walled. Average fibre length 669–1198 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands not marginal (or seemingly marginal). Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform, or confluent. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2.

Rays. Rays 12–15 per tangential mm, exclusively uniseriate. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent.

Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied. Arrangement of tiers irregular. Number of ray tiers per axial millimetre 4.

Secretory structures. Intercellular canals 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. Silica not observed.

Physical and chemical tests. Heartwood fluorescent, or not fluorescent (occasionally slightly fluorescent). Water extract fluorescent (blue); basically colourless to brown or shade of brown. Ethanol extract fluorescent (dark blue). Colour of ethanol extract colourless to brown or shade of brown to red or shade of red. Froth test positive, or negative.

Illustrations. • Transverse section. Platymiscium pinnatum. • Tangential section. Platymiscium pinnatum. Storeyed arrangement well developed in some specimens (left), not evident in others (right). • Radial section. Platymiscium pinnatum.

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.’.