Glossary: Terms used in wood anatomy for a macroscopic identification

(according to the Committee on Nomenclature of the International Association of Wood Anatomists, IAWA)

Cell-element: A general term used for an individual cell-type. Note: Used in wood anatomy, particularly to distinguish between vessels and the individual cells of which they are composed

Heartwood: The inner layers of wood which, in the growing tree, have ceased to contain living cells and in which the reserve materials (e.g. starch) have been removed or converted into heartwood substances. It is generally darker in colour than sapwood, though not always clearly differentiated (") sapwood

Fibre, Fiber: A general term of convenience in wood anatomy for the mechanical tissue of wood, i.e., any long, narrow cell of wood other than vessels and parenchyma

Wood, early: The less dense, larger-celled, first-formed part of a growth ring

Vessel: An axial series of cells that have coalesced to form an articulated tube-like structure of indeterminate length for the water transport in hardwood

Resin canal: An intercellular canal containing resin (" Intercellular canal)

Wood, semi-ring-porous: Wood in which the early wood is marked by a zone of (a) occasional large vessels, or (b) numerous small vessels; within a growth increment the transition of larger earlywood pores to smaller latewood pores is gradual

Wood, ring-porous: Wood in which the pores of the early wood are distinctly larger than those of the late wood of a growth increment and form a well-defined zone or ring

Wood, diffuse-porous: Wood in which the pores are of fairly uniform or only gradually changing size and distribution throughout a growth ring

Ray: A ribbon-like aggregate of cells (" Parenchyma) extending radially in the xylem and phloem

Ray, aggregate: A group of small, narrow, xylem rays appearing to the unaided eye or at low magnification as a single large ray

Intercellular canal: A tubular intercellular space of indeterminate length, generally serving as a repository for resin, gum, etc.

Intercellular canal, traumatic: A canal formed in response to injury to the living tree. Note: often abnormal in size and may be axial or radial

Growth ring: A layer of wood produced apparently during one growing period; frequently, especially in woods of the temperate zones, divisible into early and late wood (" Growth ring)

Lumen (Lumina): The cell cavity

Parenchyma: Tissue composed of cells that are typically brick-shaped or isodiametric; occurred in axial (axial parenchyma) and radial (" ray parenchyma) direction. Primarily concerned with the storage and distribution of food materials

Parenchyma, apotracheal: Axial parenchyma typically independent of the pores or vessels. Note: This includes diffuse and diffuse-in-aggregates apotracheal parenchyma

Parenchyma, aliform (lozenge type): Paratracheal parenchyma with rombical (lozenge) lateral extensions, as seen in cross section

Parenchyma, confluent: Coalesced aliform parenchyma forming irregular tangential or diagonal bands, as seen in cross section

Parenchyma, diffuse and diffuse-in-aggregates: Single apotracheal parenchyma strands or cells (diffuse, macroscopically usually not discernable) or short tangential clusters (diffuse-in-aggregates) distributed irregularly among fibres, as seen in cross section

Parenchyma, aliform (wing-like): Paratracheal parenchyma with wing-like lateral extensions, as seen in cross section

Parenchyma, banded: Axial parenchyma forming concentric lines or bands, as seen in cross section

Parenchyma, scalariform: A descriptive term for the ladder-like pattern formed on the cross section by rays and regularly spaced bands or lines of axial parenchyma when the latter are distinctly narrower than the rays

Parenchyma marginal: Parenchyma cells occurring either singly or forming a more or less continuous layer of variable width at the beginning (initial) or close (terminal) of a season's growth

Parenchyma, reticulate: A descriptive term for the net-like pattern formed on the cross section by rays and regularly spaced bands or lines of axial parenchyma when the bands or lines and the rays are of about the same width and distance apart

Parenchyma, paratracheal: Axial parenchyma associated with the vessels or vascular tracheids

Parenchyma, vasicentric: Paratracheal parenchyma forming a complete sheath around a vessel, of variable width and circular or slightly oval in cross section

Sapwood: The portion of the wood that in the living tree contains living cells and reserve materials, e.g. starch (" Heartwood)

Storied structure: A term applied to the axial cells and rays in wood when these are arranged in horizontal series on tangential surfaces. The presence of storied structures is the cause of the ripple marks visible with the unaided eye

Tylosis (tyloses): An outgrowth from an adjacent ray or axial parenchyma cell through a pit cavity in a vessel wall, partially or completely blocking the vessel lumen

Growth ring: A layer of wood produced apparently during one growth period; frequently especially in woods of the temperate zones, divisible into early and late wood. The growth rhythm of tropical woods is determined by the alternation of wet and dry seasons, which can only occur once a year (annual rhythm) or several times. Depending on the number of rainy seasons, several growth zones can be observed within one year. The growth zones of the tropical wood types do not necessarily correspond to annual rings