Commercial Timbers


H. G. Richter and M. J. Dallwitz

Guaiacum spp. (Pockholz, lignum vitae)

Nomenclature etc. ZYGOPHYLLACEAE. G. officinale L., G. sanctum, G. coulteri A. Gray. Trade and local names: G. officinale: Pockholz (DE) guajak (CZ, RU, HU); gaiac (FR); guaiacum wood (GB); pockhout (NL); gwajak (PL); guaiac (RO); guayacán (ES, VE); lignum vitae (US, GB); palo santo (CU, MX); Domingo- Jamaika- Panama Pockholz, Franzosenholz (DE); G. sanctum, G. coulteri: guayacan blanco, palo santo (cAm); Mexiko-Pockholz (DE); lignum vitae (US); guayacancillo (MX). Listed in CITES Annex II (the 3 commercial species).

Description based on 8 specimens. 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. Density 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 (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); 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.

Secretory structures. Intercellular canals absent.

Mineral inclusions. Crystals not observed. Silica not observed.

Illustrations. • Macro images. Guaiacum officinale. Transverse. Tangential. • 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.

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.’.