Ray
Definition
A ribbon of cells running radially (outward from the centre) through wood, carrying materials horizontally and storing starch. Ray width (in cell count), height, and cell type are major identification characters.
- Composition
- Parenchyma cells oriented radially from pith to bark
- Function
- Transport water and nutrients sideways; store starch
- Diagnostic features
- Width (cell count), height, and cell type measured on tangential sections
Common questions
What is a ray in wood?+
A ray is a ribbon of cells that runs radially outward from the center of a tree through the wood. These cells transport water, nutrients, and other materials sideways across the tree trunk and store starch. Ray width, height, and cell type help scientists identify and distinguish different wood species.
Why do forensic experts measure rays?+
Ray width (measured in cell count), height, and cell composition are diagnostic features that differ between wood species. By examining rays on tangential sections under a microscope, examiners can accurately identify which tree a piece of wood came from, which is useful in cases involving timber or wooden objects.
How are rays positioned in wood?+
Rays extend radially from the pith (the center) all the way out to the bark, arranged like spokes on a wheel. They are made of parenchyma cells, which handle transport and storage functions.
Related terms
- Diffuse-porous
- A vessel arrangement in which pores of broadly similar size are distributed throughout the growth ring without a distinct early-wood band of...
- IAWA feature list
- A standardized set of coded anatomical characters published by the International Association of Wood Anatomists for hardwoods (1989) and softwoods (2004), used...
- InsideWood
- A peer-reviewed online database at North Carolina State University containing anatomical descriptions and photomicrographs for over 9,000 hardwood species, used as a...
- Parenchyma
- Thin-walled, roughly spherical or elongated cells that form the bulk of soft plant tissues, including the leaf mesophyll. They are the most...
- Resin canal
- An intercellular space lined with secretory epithelial cells that produce resin. Present in many conifers and a small number of hardwoods. In...
- Ring-porous
- A vessel arrangement in which the early-wood (spring) ring contains conspicuously large vessels and the late-wood contains small ones, creating a sharp...
- Ring-porous vs. diffuse-porous
- In ring-porous woods, large vessels form a distinct band in early wood and smaller vessels in late wood. In diffuse-porous woods, vessel...
- Tracheid
- The primary water-conducting and mechanical cell of softwoods (conifers). Elongated, pointed at both ends, and lacking a perforation plate: water passes through...
- Vessel
- A conducting cell in hardwood (angiosperm) xylem, visible on a cross-section as a pore. Vessel arrangement, diameter, grouping, and wall features are...
- Vessel (pore)
- A series of cells joined end to end with perforation plates dissolved away, forming a continuous water-conducting tube. Characteristic of hardwoods (angiosperms)....
Explained in these topics
- Wood Anatomy and Microscopic IdentificationA ribbon of cells running radially (outward from the centre) through wood, carrying materials horizontally and storing starch. Ray width (in cell count), heigh...
- Wood Anatomy and Timber IdentificationA ribbon of parenchyma cells oriented radially from pith to bark, transporting water and nutrients laterally. Ray width (in cells) and height are diagnostic an...