Commercial Timbers

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H. G. Richter and M. J. Dallwitz

Avicennia officinalis L. (api-api)

Nomenclature etc. AVICENNIACEAE. Not protected under CITES regulations.

Description based on 7. Tree. Geographic distribution: India, Pakistan, Sri Lanka and Burma.

General. Growth ring boundaries indistinct or absent. Heartwood basically brown and white or grey, with streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.56–0.8 g/cm³. Wood of commercial potential.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern (with tendency towards radial alignment), in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 80 µm; diameter of vessel lumina: medium. Average number of vessels/mm² 14; vessels per square millimetre few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 3 µm, minute, 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 in vessels absent. Other deposits in heartwood vessels present (yellowish brown).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres 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 paratracheal. Paratracheal axial parenchyma scanty, vasicentric, and aliform. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–4(–6). Unlignified parenchyma absent.

Rays. Rays present, 9–12(–14) per tangential mm, multiseriate (also if only few), (1–)2–4(–10) cells wide, of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of two distinct sizes. Height of large rays commonly 500 to 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with procumbent, square and upright cells mixed throughout the ray. Sheath cells present. 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 present, concentric. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic, styloids or elongate, and in other forms (few small cubic crystals), located in ray cells. Crystal-containing ray cells upright and/or square and procumbent, upright and/or square ray cells not chambered. Crystals in procumbent ray cells not in radial alignment. Cystoliths absent. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives leaching out when in contact with water. Ethanol extract fluorescent (weakly greenish). Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative. Splinter burns to charcoal.

Illustrations. • Transverse section. Avicennia germinans. • Tangential section. Avicennia germinans. • Radial section. Avicennia germinans.


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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’.

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