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H. G. Richter and M. J. Dallwitz

Corylus avellana L. (Haselnuss, hazel)

Nomenclature etc. BETULACEAE / CORYLACEAE. + Corylus colurna L. Trade and local names: Haselnuss, Corylus colurna L. = Baumhasel (DE); noisetier, coudrier (FR); hazel (GB); nocciolo, avellano (IT); avellano (ES); aveleira (PT); hassel (DK, SE); hazelaar (NL). Not protected under CITES regulations.

Description based on 7 specimens. Tree, or shrub. Geographic distribution: Europe, excl. Mediterranean to temperate Asia.

General. Growth ring boundaries distinct. Only Corylus colurna L. becomes a tree of up to 20 m in height and 50 cm in diameter. Heartwood basically light brown, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.53–0.63 g/cm³. Wood of commercial potential, or of no commercial potential. Only Corylus colurna has limited commercial potential; the heartwood is darker brown and easily distinguished from the lighter coloured sapwood.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern (radial), in multiples, commonly short (2–3 vessels) radial rows or radial rows of 4 or more. Two distinct vessel diameter classes absent. Average tangential vessel diameter 30–60 µm; diameter of vessel lumina: small. Average number of vessels/mm² 60–100; vessels per square millimetre numerous to very numerous. Perforation plates scalariform, with 5–10 bars. Intervessel pits alternate, average diameter (vertical) 5–7 µm, small, not vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings present, in narrow and wide vessel elements, throughout the body of vessel elements. Tyloses in vessels absent. Other deposits in heartwood vessels not observed, helical thickenings very fine, not in all vessels.

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 or distinctly bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma not banded. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse, or diffuse-in-aggregates. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 5–8. Unlignified parenchyma absent.

Rays. Rays 15–18 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 present. Rays of one size. Height of large rays up to 500 µm, or 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 (very rarely with two marginal rows). 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 or not observed, prismatic, located in ray cells. Crystal-containing ray cells procumbent. Number of crystals per cell or chamber one. Crystal containing cells of normal size, or enlarged (idioblasts). Cystoliths absent. Crystals extremely rare, not in all specimens present. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent.

Illustrations. • Transverse section. Corylus avellana. • Tangential section. Corylus avellana. • Radial section. Corylus avellana.


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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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