|
| Commercial timbers |
Nomenclature etc. APOCYNACEAE. Additional species: Dyera polyphylla (Miq.) v. Steenis. Trade and local names: yeluu-tong, luu-tong (MY); jelutung (ID); teen-pet daeng (TH). Not protected under CITES regulations.
Description based on 4 specimens. Tree. Geographic distribution: Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Heartwood basically yellow. Sapwood colour similar to heartwood colour. Density 0.3–0.5 g/cm³.
Vessels. Vessels present. Wood diffuse porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more. Average tangential vessel diameter 90–140–160 µm. Average number of vessels/mm² 3–10. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–7 µm, pits vestured or not vestured. Intervessel pits described as: "obscurely vestured" (Lemmens & al. 1995: PROSEA 5(2), Timber trees: Minor commercial species). Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type. Helical thickenings absent. Tyloses absent.
Tracheids and fibres. Fibres very thin-walled, or of medium wall thickness. Average fibre length 900–1500 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered or distinctly bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse, or diffuse-in-aggregates (forming a subtle network between rays). Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 2–4.
Rays. Rays 4–8 per tangential mm, multiseriate, (1–)2–4 cells wide. 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 or mostly 2–4 marginal rows of upright or square cells.
Storied structures. Storied structure absent.
Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes present (laticifers in rays). Wood often forms large and dark latex traces.
Mineral inclusions. Crystals not observed. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Froth test negative.
Illustrations. • Macroscopic images. transverse (ca. 10x). longitudinal (natural size). • Transverse section. • Tangential section. latex tubes in rays (blow-up left). • 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’.
