| | Commercial timbers |
Nomenclature etc. APOCYNACEAE. Incl. Wrightia pubescens R.Br. (syn. W. annamensis Eberh. & Dubard), W. arborea (Dennst.) Mabb. (syn. W. tomentosa Roem. & Schult.). Trade and local names: lanete (RP); mentaos, bintaos (RI); jeliti (MAL); mok-man (T). Not protected under CITES regulations.
Description based on 2 specimens one each for the species W. annamensis, W. tomentosa. Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. Wood of commercial potential.
Vessels. Vessels present. Wood diffuse porous. Vessels arranged in a diagonal and/or radial pattern and no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows and in radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 20–50–90 µm; diameter of vessels: small. Average number of vessels/mm² (15–)25–30(–60); vessels per square millimetre moderately numerous. W. annamensis: 15–30 vessels per mm², W. arborea: 50–60 vessels per mm². Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3–4 µm, average diameter (vertical) minute, pits not 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 absent. Other deposits not observed.
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled and of medium wall thickness. 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 apotracheal and paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 4–6. Unlignified parenchyma absent.
Rays. Rays present, 12–25 per tangential mm, multiseriate, 1–2 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 and commonly 500 to 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 2–4 marginal rows of upright or square cells and with more than 4 marginal rows 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 absent.
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. Crystal-containing ray cells procumbent, upright and/or square ray cells chambered. Crystals in procumbent ray cells not in radial alignment. Cystoliths absent. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent; colour of water extract colourless to brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown. Chrome azurol-S test negative. Froth test positive. Splinter burns to partial ash. Ash yellow-brown.
Illustrations. • Transverse section. Wrightia arborea. Wrightia annamensis. • Tangential section. Wrightia arborea. • Radial section. Wrightia arborea.
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’.
