Commercial Timbers


H. G. Richter and M. J. Dallwitz

Crataegus spp. (Weißdorn, hawthorn, may tree)

Nomenclature etc. ROSACEAE. Species included in the description: C. azarolus L. (1), C. coccinea L. (1), C. laevigata (Poir.) DC (1), C. melanocarpa Bieb. (1), C. monogyna Jacq. (1), C. oxycantha L. (4), C. pinnatifida Bunge (1). Trade and local names: Weißdorn (DE); hawthorn (GB, US); aubépin, noble épin (FR); bianco spino (IT); espino blanco (ES); ak diken (TR). Not protected under CITES regulations.

Tree. Geographic distribution: Europe, excl. Mediterranean, Mediterranean incl. N. Africa and Middle East, temperate Asia, and North America.

General. Growth ring boundaries distinct. Growth ring limites marked by radially flattened and thick walled fbres (latewood). Odour indistinct or absent. Density 0.8–0.9 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples (vessels exclusively solitary in: C. coccinia, C. monogyna), commonly short (2–3 vessels) radial rows. Vessel outline angular. Two distinct vessel diameter classes absent. Vessel multiples often with diagonal or tangential orientation. Average tangential vessel diameter (20–)30(–45) µm; diameter of vessel lumina: small. Average number of vessels/mm² 160–300; vessels per square millimetre very numerous. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–8 µm, medium, not vestured. Very few pits, mostly in just one vertical row. Vessel-ray pits with distinct borders, similar to intervessel pits (but smaller), 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 not observed.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres 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 and diffuse-in-aggregates (short lines of parenhyma in: C. laevigata, C. monogyna). Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–6.

Rays. Rays present, (8–)10–12(–15) per tangential mm, multiseriate (also if only few), 1–3(–5) 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 distinct and 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 and not observed, 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 and enlarged (idioblasts). Cystoliths absent. Crystals observed in: C. azarolobus, C. coccinia, C. oxycantha. 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 positive (froth test weakly positive). Splinter burns to partial ash. Ash white to grey.

Illustrations. • Transverse section. Crataegus coccinea. • Tangential section. Crataegus aestivalis. • Radial section. Crataegus aestivalis.

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.’.