Nomenclature etc. RUTACEAE. Syn.: Esenbeckia riedeliana Engl., Helietta multiflora Engl. Trade and local names: guatambú (PY, AR); pau marfim (BR); guatambú morotó, ibirá ñotí (AR). Not protected under CITES regulations.
Description based on 5 (specimens). Tree. Geographic distribution: tropical South America to temperate South America.
General. Growth ring boundaries distinct. Growth ring limits marked by marginal parenchyma bands with an increased number of prismatic crystals, and widened rays. Heartwood basically yellow white or grey, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.7–0.9 g/cm³.
Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 60–100 µm; diameter of vessel lumina: medium. Average number of vessels/mm² 30–45; vessels per square millimetre moderately numerous and numerous. Average vessel element length 200–330–500 µm. Average vessel element length short and medium. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–4 µm, minute, 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 (yellow).
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness to very thick-walled. Average fibre length 990–1400–2100 µm. Average fibre length medium and long. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.
Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty to vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4. Unlignified parenchyma absent.
Rays. Rays present, 5–9 per tangential mm, multiseriate (also if only few), 2–4 cells wide, narrow (2–3 seriate) and of medium width (3–5 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 to commonly 500 to 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls distinct.
Storied structures. Storied structure absent.
Secretory structures. Oil and mucilage cells absent. Intercellular canals present, traumatic origin, axial type, in long tangential lines and in short tangential lines. Laticifers or tanniniferous tubes absent.
Cambial variants. Included phloem absent. Other cambial variants absent.
Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square and procumbent, upright and/or square ray cells chambered and not chambered. Crystals in procumbent ray cells not in radial alignment. 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 fluorescent (weakly yellowish). Water extract fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent (bright yellow). Colour of ethanol extract yellow or shade of yellow. Chrome azurol-S test negative. Splinter burns to partial ash. Ash white to grey.
Illustrations. • Transverse section. Balfourodendron riedelianum. • Tangential section. Balfourodendron riedelianum. • Radial section. Balfourodendron riedelianum.
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. http://delta-intkey.com’.