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H. G. Richter and M. J. Dallwitz

Eucalyptus globulus Labill. (Blue gum, "globulus")

Nomenclature etc. MYRTACEAE. Not protected under CITES regulations.

Description based on 10 specimens. Tree. Geographic distribution: Mediterranean incl. N. Africa and Middle East, Australia, southern Africa, North America, and temperate South America.

General. Growth ring boundaries distinct and indistinct or absent. Growth ring limits, if distinct, indicated by dark latewood zones nearly void of vessels. Heartwood basically brown, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Often with interlocked grain.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern and no specific pattern, exclusively solitary. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 60–170–230 µm; diameter of vessel lumina: large. Average number of vessels/mm² 4–6; vessels per square millimetre very few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 8–10 µm, medium. Vessel-ray pits with reduced borders or apparently simple, rounded or angular, 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 commonly present. Fibres very thin-walled and of medium wall thickness. Fibre pits common in both radial and tangential walls, distinctly bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse. Paratracheal axial parenchyma scanty and vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (3–)4–6(–7). Unlignified parenchyma absent.

Rays. Rays present, 10–14 per tangential mm, multiseriate (also if only few), 1–2(–3) 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 a single cell type (homocellular) and two or more cell types (heterocellular); homocellular ray cells procumbent. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row 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 axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Crystals of very variable occurence in different specimens. Silica not observed.

Physical and chemical tests. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract not 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 white to grey and yellow-brown.

Illustrations. • Transverse section. Eucalyptus globulus. • Tangential section. Eucalyptus globulus. • Radial section. Eucalyptus globulus.


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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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