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| Commercial timbers |
Nomenclature etc. FABACEAE-FABOIDEAE. Trade and local names: mai payung (TH); kran houng (KH); trac (VN). Listed in CITES Annex II.
Description based on 6 specimens. Tree. Geographic distribution: Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia.
General. Growth ring boundaries distinct or indistinct or absent. Heartwood basically brown (leather to almost black brown, sometimes with a slight purplish hue); with streaks. Sapwood colour distinct from heartwood colour. Odour distinct (rather unpleasant). Density 0.98–1.06 g/cm³.
Vessels. Wood diffuse porous. Vessels in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more. Average tangential vessel diameter 150–190(–250) µm. Average number of vessels/mm² (1–)2–4. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) (7–)9–11(–12) µm, pits vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits present.
Tracheids and fibres. Fibres very thick-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma banded or not banded. Bands marginal (or seemingly marginal) or not marginal (or seemingly marginal). Axial parenchyma bands forming a reticulate pattern with rays. Bands fine. Parenchyma bands very fine, often discontinuous. Axial parenchyma apotracheal (mainly), or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma aliform. Aliform parenchyma of the winged type. Axial parenchyma as strands. Average number of cells per strand: 1–2.
Rays. Rays (8–)10–14 per tangential mm, multiseriate, 1–2(–3) cells wide. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent.
Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres not storied. Number of ray tiers per axial millimetre 5–7.
Secretory structures. Intercellular canals absent.
Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (light green); colour of water extract colourless to brown. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown (dark brown). Froth test positive. Splinter burns to full ash, or to partial ash. Ash white to grey, or yellow-brown (different specimens = variable ash colour).
Illustrations. • Macroscopic images. transverse (ca. 10x). tangential (natural size). • Transverse section. • Transverse section, enlarged. axial parenchyma mainly diffuse-in-aggregates. • Tangential section. • Radial section.
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: 9th April 2019. delta-intkey.com’.
