Commercial Timbers


H. G. Richter and M. J. Dallwitz

Myrocarpus frondosus Fr. Allem.(Incienso)

Nomenclature etc. FABACEAE-FABOIDEAE. Trade and local names: incienso, yvyra paje, kavure'y (PY); cabriúva-parda, bálsamo,bálsamo cabureiba, miroé, óleo-de-caboreiba, óleo-pardo, caboré, cabriúva-preta, óleo vermelho, cabriúna, miroé (BR); incienso colorado, incienso negro, incienso amarillo, incienso blanco, ivirapayó (AR); incienso (UY); common sassafras, sassafras (US). Not protected under CITES regulations.

Tree. Geographic distribution: southern Brazil and temperate South America.

General. Growth ring boundaries distinct. Growth ring boundaries demarcated by fine (1–2 cells thick) , somewhat wavy and sometimes discontinuous marginal and by a slight thickening of rays parenchyma bands. Heartwood basically brown and red, with streaks. Sapwood colour distinct from heartwood colour. Odour distinct (pleasant, similar to myrrh). Density 0.84–0.91 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 30–60–100 µm; diameter of vessel lumina: medium. Vessels per square millimetre moderately numerous. Average vessel element length 160–180 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–5 µm, small, 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, with many dark brown organic inclusions in most vessels.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness to very thick-walled. Average fibre length 900–1400 µm. Average fibre length medium. 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), bands much wider than rays, fine, up to three cells wide. Parenchyma bands short or longer, sometimes wavy or forming short arcs. Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma lozenge and winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4. Unlignified parenchyma absent.

Rays. Rays present, multiseriate (also if only few), 2(–3) 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) and two or more cell types (heterocellular); homocellular ray cells procumbent. 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 indistinct or absent. Heterocellular rays (1 marginal row of square cells) present but rare.

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 4–5. Storied structure sometimes irregular.

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 ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells 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. Crystals in marginal ray cells infrequent. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent; basically colourless to brown or shade of brown. Ethanol extract fluorescent. Colour of ethanol extract yellow or shade of yellow. Water extract light blue, ethanol extract blue. Chrome azurol-S test negative. Froth test negative. Splinter burns to charcoal.

Illustrations. • Transverse section. Myrocarpus frondosus. • Tangential section. Myrocarpus frondosus. • Radial section. Myrocarpus frondosus.

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.’.