Commercial timbers

H. G. Richter and M. J. Dallwitz

Balfourodendron riedelianum (Engl.) Engl. (Guatambú)

Nomenclature etc. RUTACEAE. Synon.: Esenbeckia riedeliana Engl., Helietta multiflora Engl. Trade and local names: Guatambú (PY, RA); pau marfim (BR); guatambú morotó, ibirá ñotí (RA). Status of protection under CITES regulations: not protected.

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. Basic specific gravity 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. Average tangential 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 and 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, 2–3 cells wide and commonly 3–5 cells wide. 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 rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 1. 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. Water extract basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent (bright yellow). Ethanol extract basically yellow or shade of yellow. Chrome azurol-S test negative. Splinter burns to partial ash. Ash white to grey.