Commercial timbers

H. G. Richter and M. J. Dallwitz


Guaiacum spp. (Pockholz, lignum vitae)

Nomenclature etc. ZYGOPHYLLACEAE. G. officinale L., G. sanctum, G. guatemalense Planch ex Hemsl. Trade and local names: G. officinale: Pockholz (D) guajak (CS, RUS, H); gaiac (F); guaiacum wood (GB); pockhout (NL); gwajak (PL); guaiac (RO); guayacan (E, YV); lignum vitae (USA, GB); palo santo (C, MEX) Domingo- Jamaika- Panama Pockholz, Franzosenholz (D); G. sanctum: guayacan blanco, palo santo (cAm); Mexiko- Pockholz (D); lignum vitae (USA); guayacancillo (MEX). Status of protection under CITES regulations: G. officinale and G. sanctum in annex II; G. coulteri not protected.

Tree. Geographic distribution: Mexico and Central America, Caribbean, and tropical South America.

General. Growth ring boundaries distinct and indistinct or absent. Heartwood basically brown to black brown to green, with streaks. Sapwood colour distinct from heartwood colour. Odour distinct. Basic specific gravity 950–1200–1300 g/cm³. With greasy surface.

Vessels. Wood diffuse-porous. Vessels exclusively solitary. Two distinct vessel diameter classes present and absent. Average tangential vessel diameter 15–68–80 µm. Average number of vessels/mm² 6–10–14. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 2–4 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits in heartwood vessels present (greenish-black, also in trasition zone from sapwood to heartwood).

Tracheids and fibres. Fibres very thick-walled. Average fibre length 440–590–830 µm. Fibre pits common in both radial and tangential walls, distinctly bordered.

Axial parenchyma. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty, vasicentric, and unilateral paratracheal (incomplete vasicentric). Axial parenchyma as strands. Average number of cells per axial parenchyma strand (1–)2–4.

Rays. Rays (12–)17–19 per tangential mm, exclusively uniseriate. Rays composed of a single cell type. Homocellular ray cells procumbent.

Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied. Number of ray tiers per axial millimetre 8–10.

Mineral inclusions. Crystals not observed. Silica not observed.

Miscellaneous. • Transverse section. Guaiacum sanctum. Note: Solitary vessels of different sizes (V), with very thick cell walls. «---V. «---V. «---V. • Tangential section. Guaiacum sanctum. Note: Uniseriate rays, storied structure, fusiform parenchyma. • Radial section. Guaiacum sanctum.


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