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Nomenclature etc. ROSACEAE. + Sorbus aria (L.) Crantz, S. intermedia (Ehrh.) Pers. Trade and local names: S. aria: Mehlbeere (DE); alisier blanc (FR); whitebeam (GB); sorbo montano, farinaccio (IT); serbal blanco (ES). Not protected under CITES regulations.
Description based on 15 specimens. Tree. Geographic distribution: Europe, excl. Mediterranean, temperate Asia.
General. Growth ring boundaries distinct. Demarcated by radially flattened, thick-walled fibres (latewood). Heartwood basically brown and red; with streaks and without streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.57–0.64–0.78 g/cm³.
Vessels. Vessels present. Wood semi ring porous and diffuse porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows and in clusters. Vessel outline rounded and angular. Two distinct vessel diameter classes absent. Average tangential vessel diameter 50–60 µm; diameter of vessels: medium. Vessels per square millimetre very numerous. Perforation plates simple, scalariform, and reticulate, foraminate or other types, with scalariform and reticulate perforations very rare. Intervessel pits alternate, average diameter (vertical) 5–6 µm, average diameter (vertical) small, pits not vestured. Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings present, in narrow and wide vessel elements, throughout the body of vessel elements. Tyloses absent. Other deposits present and not observed.
Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. 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. Axial parenchyma as strands. Average number of cells per strand: 2–4. Unlignified parenchyma absent. Short lines more frequent in latewood and along growthring limits but not forming (marginal) bands.
Rays. Rays present, 10–15 per tangential mm, multiseriate, 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 (extremely rare) or not observed, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.
Physical and chemical tests. Heartwood fluorescent. Water extract not fluorescent; colour of water extract colourless to brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown. Chrome azurol-S test negative. Froth test positive. Splinter burns to partial ash. Ash dark grey to black.
Illustrations. • Transverse section. semi-ringporous (left) and diffuse porous (right) specimen. • Tangential section. • Radial section. prismatic crystals in chambered axial parenchyma cells »».
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: 9th April 2019. delta-intkey.com’.
