Commercial Timbers

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H. G. Richter and M. J. Dallwitz

Brosimum spp. (Amapá)

Nomenclature etc. MORACEAE. Species included in the description: Brosimum potabile Ducke (2), Brosimum parinarioides var. parinarioidesDucke (1). Trade and local names: amapá, amapá dulce (BR). Not protected under CITES regulations.

Description based on 3 specimens. Tree. Geographic distribution: tropical South America.

General. Growth ring boundaries indistinct or absent. Heartwood basically brown and white or grey, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.5–0.6 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows, radial rows of 4 or more, and in clusters. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 130–180–250 µm; diameter of vessel lumina: large. Average number of vessels/mm² 3–5; vessels per square millimetre very few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 8–11 µm, medium and large, not vestured. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits, horizontal to vertical, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels 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. Many pits in fibres.

Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (2–)4–6. Unlignified parenchyma absent.

Rays. Rays present, 4–6 per tangential mm, multiseriate (also if only few), (1–)2–4 cells wide, narrow (2–3 seriate) and of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays 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 1 marginal row of upright or square cells and mostly 2–4 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. Two marginal rows occasionally observed in B.potabile.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes present. Latex tubes with brown contents.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals not observed. Cystoliths absent. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative. Splinter burns to partial ash. Ash bright white.

Illustrations. • Transverse section. Brosimum potabile. • Tangential section. Brosimum parinarioides. Right: Latex tube in ray. • Radial section. Brosimum potabile.


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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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