Commercial Timbers


H. G. Richter and M. J. Dallwitz

Bulnesia arborea Engl. (Vera), B. sarmientoi Lorentz ex Griseb. (Palo santo)

Nomenclature etc. ZYGOPHYLLACEAE. Trade and local names: verawood, vera (trade); palo santo (PY, AR); ibiocaí (AR). Not protected under CITES regulations.

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

General. Growth ring boundaries distinct. Growth ring limits indicated by many and large vessels in earlywood. Heartwood basically brown, black, and green (varying in colour from light olive green to chocolate brown; surface of fresh wood often turns dark green upon exposure), with streaks. Sapwood colour distinct from heartwood colour (sapwood mostly thin and light yellow in color). Density 0.92–1.1 g/cm³. Very expressive figure (striping and "feather"-like) due to pronounced interlocked grain in narrow zones and the diverging angle between vessel trajectories.

Vessels. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern and dendritic pattern, in multiples, commonly short (2–3 vessels) radial rows and in clusters. Average tangential vessel diameter (45–)60(–100) µm; diameter of vessel lumina: small to medium. Average number of vessels/mm² 35–115; vessels per square millimetre moderately numerous to very numerous. Average vessel element length 80–125 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, small, 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 present, nearly black organic deposits.

Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness to very thick-walled. Average fibre length 500–900 µm. Average fibre length short. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded and not banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse. Paratracheal axial parenchyma scanty, vasicentric, and confluent. Axial parenchyma fusiform. Unlignified parenchyma absent. Apotracheal axial parenchyma generally crystalliferous.

Rays. Rays 10–12 per tangential mm, multiseriate (also if only few), 1–2 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 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. Biseriate rays more common in Bulnesia sarmientoi.

Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied. Arrangement of tiers regular (horizontal or straight). Number of ray tiers per axial millimetre 8–12.

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 not fluorescent; basically colourless to brown or shade of brown, or yellow or shade of yellow. Ethanol extract fluorescent (light blue to purple). Colour of ethanol extract yellow or shade of yellow. Chrome azurol-S test negative. Froth test negative. Splinter burns to charcoal.

Illustrations. • Macro images. Bulnesia arborea. Transverse. Radial. • B arborea: Transverse section. Bulnesia arborea. • B. arborea: Tangential section. Bulnesia arborea. • B. arborea: Radial section. Bulnesia arborea. Inset: Large prismatic crystals in chambered axial parenchyma cells. • B. sarmientoi: Tansverse section. Bulnesia sarmientoi. • B. sarmientoi: Tangential section. Bulnesia sarmientoi. • B. sarmientoi: Radial section. Bulnesia sarmientoi. Inset: Large prismatic crystals in chambered axial parenchyma cells.

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.’.