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| Commercial timbers |
Nomenclature etc. RUBIACEAE. Trade and local names: palo blanco (AR, PE, PY); ibirá-morotí (AR); verdolaga (BO). Not protected under CITES regulations.
Description based on 5 specimens. Tree. Geographic distribution: tropical South America, southern Brazil, temperate South America.
General. Growth ring boundaries distinct (indicated by latewood zones of low vessel frequency). Heartwood basically white or grey to yellow, white or grey to brown (occasionally with yellowish-brown discoloured heartwood; only the light coloured sapwood is traded). Sapwood colour similar to heartwood colour, or distinct from heartwood colour (only if discoloured heartwood is present). Density 0.75–0.95 g/cm³.
Vessels. Wood diffuse porous. Vessels arranged in a diagonal and/or radial pattern or no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more (rarely). Average tangential vessel diameter 30–50–70 µm. Average number of vessels/mm² 100–140. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–6 µm, pits vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses only in discoloured heartwood present or absent, thinwalled.
Tracheids and fibres. Fibres of medium wall thickness, or very thick-walled. Average fibre length 900–1000–1200 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate; evenly distributed. Septa of regular occurrence but infrequent, 1–2 per fibre.
Axial parenchyma. Axial parenchyma absent or extremely rare.
Rays. Rays 12–15 per tangential mm, multiseriate (uniseriate rays however frequent, up to 50% of the total), 1–3 cells wide. Rays of two distinct sizes. Height of large rays commonly 500 to 1000 µm. Rays composed of only some uniseriate rays a single cell type (homocellular), or two or more cell types (heterocellular); homocellular ray cells square or upright. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells or mostly 2–4 marginal rows of upright or square cells or with more than 4 marginal rows of upright or square cells. Disjunctive ray parenchyma end walls distinct.
Mineral inclusions. Crystals present, in form of crystal sand, located in ray cells. Crystal-containing ray cells upright and/or square or procumbent (rarely in procumbent cells). Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (light blue); colour of water extract colourless to brown. Ethanol extract fluorescent (light blue). Colour of ethanol extract colourless to brown. Splinter burns to full ash. Ash white to grey.
Illustrations. • Transverse section. • Tangential section. • Radial section. • Crystal sand. crystal sand (CR) in marginal and body ray cells. CR. CR. CR. • Septate fibres. presence of septate fibres.
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’.
