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Nomenclature etc. ZYGOPHYLLACEAE. Trade and local names: B. arborea: verawood, Maracaibo lignum-vitae (trade); i guayacán (BO); bois de gaïac (FR); guaico (IT); guayacán de bola (CO); bera, cuchivaro, vera aceituna (VE); B. sarmientoi: biocaí, ybira ocaí (AR); Argentine lignum-vitae, holy wood (US);. Not protected under CITES regulations (B. arborea), or listed in CITES Annex II (B. sarmientoi).
Description based on 5 specimens. Tree. Geographic distribution: tropical South America (B. arborea: Colombia and Venezuela), southern Brazil, temperate South America (B. sarmientoi: Argentina, Bolivia, Paraguay).
General. Growth ring boundaries distinct (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 (stripes 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 a diagonal and/or radial pattern and a dendritic pattern, in multiples, commonly in short (2–3 vessels) radial rows or in clusters. Average tangential vessel diameter (45–)60(–100) µm. Average number of vessels/mm² 35–115. Average vessel element length 80–125 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits present (nearly black organic deposits).
Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness, or very thick-walled. Average fibre length 500–900 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Apotracheal axial parenchyma diffuse, or diffuse-in-aggregates. Paratracheal axial parenchyma scanty, vasicentric, and confluent. Axial parenchyma fusiform. Apotracheal axial parenchyma generally crystalliferous.
Rays. Rays 10–12 per tangential mm, multiseriate, (1–)2 cells wide. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent. 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. Number of ray tiers per axial millimetre 8–12.
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 not fluorescent. Water extract not fluorescent; colour of water extract colourless to brown, or yellow. Ethanol extract fluorescent (light blue to purple). Colour of ethanol extract yellow. Splinter burns to charcoal.
Illustrations. • Macroscopic images: Bulnesia arborea. transverse (ca. 10x). radial (natural size). Bulnesia arborea. • Macroscopic images: Bulnesia sarmientoi. transverse (ca. 10x). tangential (natural size). Bulnesia sarmientoi. • B arborea: Transverse section. Bulnesia arborea. • B. arborea: Tangential section. Bulnesia arborea. • B. arborea: Radial section. Bulnesia arborea. 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. 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: 9th April 2019. delta-intkey.com’.
