Nomenclature etc. FABACEAE-FABOIDEAE. Myroxylon balsamum Harms, M. peruiferum L. Trade and local names: cabriuva vermelha, bálsamo, sangue de gato, oleo vermelho (BR); incienso, i. colorado, quina (AR, PY); estoraque, quina-quina (PE); sándalo (EC); bálsamo de tolu (CO). Not protected under CITES regulations.
Tree. Geographic distribution: Mexico and Central America to temperate South America.
General. Growth ring boundaries distinct or indistinct or absent. Growth ring boundaries occasionally marked by narrow and often discontiuous marginal parenchyma bands. Heartwood basically brown red, without streaks. Sapwood colour distinct from heartwood colour (sapwood cream-coloured, narrow). Odour distinct (aromatic). Density 0.77–0.9 g/cm³.
Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 110–180 µm; diameter of vessel lumina: large. Average number of vessels/mm² 10–20 (M. balsamum; 35–40 in M. peruiferum); vessels per square millimetre few to moderately numerous. Average vessel element length 200–350 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–5 µm, minute to small, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (reddish-brown contents frequent, white contents occasionally).
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness to very thick-walled. Average fibre length 700–1100 µm. Average fibre length short to medium. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.
Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty to vasicentric, or confluent. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4 (4-seriate only when in direct contact with vessels). Unlignified parenchyma absent.
Rays. Rays 8–11 per tangential mm, 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 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 indistinct or absent.
Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied. Number of ray tiers per axial millimetre 4.
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 or axial parenchyma cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells chambered or not chambered. Crystal-containing axial parenchyma cells chambered (in short, mostly 4-seriate chains). Number of crystals per cell or chamber one. Cystoliths absent. Silica not observed.
Illustrations. • Macro image. Myroxylon balsamum. Transverse. • Transverse section. Myroxylon balsamum. • Tangential section. Myroxylon balsamum. • Radial section. Myroxylon balsamum.
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’.