Commercial Timbers


H. G. Richter and M. J. Dallwitz

Astronium urundeuva (Fr. Allem.) Engl. (Urunde'y mi)

Nomenclature etc. ANACARDIACEAE. Trade and local names: urunde'y mi (PY); aroeira-do-sertão, urundeúva, aroeira preta, urindeúva, arindeúva (BR); urundel, urunday del noroeste, urunday-mi (AR); cuchi (BO). Not protected under CITES regulations.

Description based on 3 specimens. Tree. Geographic distribution: southern Brazil and temperate South America.

General. Growth ring boundaries distinct. Browth ring boundaries microscopically distinct by a darker band of thick-walled and radially flattened fibres. Heartwood basically brown and red, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.9–1.2 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 80–110–180 µm; diameter of vessel lumina: large. Average number of vessels/mm² 10–20; vessels per square millimetre few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 8–11 µm, medium and large, not vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular and horizontal to vertical, of two distinct sizes or types in the same ray cell, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present, brown organic contents.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thick-walled. Average fibre length short (ca. 900). Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres septate and non-septate. Septate fibres evenly distributed.

Axial parenchyma. Axial parenchyma present. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–6. Unlignified parenchyma absent.

Rays. Rays present, 4–8 per tangential mm, multiseriate (also if only few), 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. 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.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals present, non-traumatic origin, radial type. Radial intercellular canals few. Laticifers or tanniniferous tubes absent.

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

Mineral inclusions. Crystals present, prismatic, located in ray cells, axial parenchyma cells, and tyloses. Crystal-containing ray cells upright and/or square, upright and/or square ray cells not chambered. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one and more than one. Crystals in one cell or chamber of the same size. Crystal containing cells of normal size. Cystoliths absent. Silica not observed.

Illustrations. • Transverse section. Astronium urundeuva. • Tangential section. Astronium urundeuva. • Radial section. Astronium urundeuva. • Miscellaneous. Astronium urundeuva. Radial intercellular canal (IC) and crystal in tyloses (CR). IC. CR.

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: 25th June 2009.’.