Nomenclature etc. MELIACEAE. Syn.: S. candollei Pittier, S. krukovii Gleason, S. tessmannii Harms, S. belizensis Lundell. Trade and local names: Amerikanisches Mahagoni, echtes Mahagoni, Honduras-, Tabasco-, Nicaragua-Mahagoni (DE);, caoba (cAm), aguano (PA, PE, BR); orura (VE); zopilote (MX); sapotón (SR); yulu (NI), crura (BO); acajou d'Amérique (FR), American mahogani, baywood (GB), broadleaf mahagony (US). Listed in CITES Annex II (S. humilis, S. macrophylla, S. mahagoni, 2002).
Tree. Geographic distribution: Mexico and Central America and tropical South America (except Amazon basin).
General. Growth ring boundaries distinct. Growthring boundaries marked by marginal parenchyma bands. Heartwood basically brown (light brown) brown to red (darkening upon exposure, golden luster), without streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.4–0.5–0.65 g/cm³. Grain interlocked (ribbon figure) and/or irregular near branches or crotches (variously figured wood).
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 90–160–255 µm. Average number of vessels/mm² 2–18. Average vessel element length 480–890 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 2–4 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (mostly dark reddish brown, less frequently white).
Tracheids and fibres. Fibres of medium wall thickness. Average fibre length 700–1000–1750 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres exclusively septate, or septate and non-septate (non-septate fibres few). Septate fibres evenly distributed.
Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide or coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty to vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–8.
Rays. Rays 5–10 per tangential mm, multiseriate (also if only few), 1–2–4(–5) cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Rays composed of a single cell type (homocellular), or two or more cell types (heterocellular); homocellular ray cells procumbent, or 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. Sheath cells absent. Tile cells absent.
Storied structures. Storied structure present or absent, all rays storied, axial parenchyma storied, vessel elements storied. Arrangement of tiers regular (horizontal or straight), or irregular. Storied rays not in all specimens present.
Secretory structures. Intercellular canals present or absent, traumatic origin, axial type, rarely in long tangential lines or in short tangential lines. Laticifers or tanniniferous tubes absent.
Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square and procumbent (infrequent in procumbent ray cells). Number of crystals per cell or chamber one. Silica not observed.
Illustrations. • Macro images. Swietenia macrophylla. Transverse. Radial. • Transverse section. Swietenia macrophylla. • Tangential section. Swietenia macrophylla. • Radial section. Swietenia macrophylla.
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’.