Ray
/reɪ/
Definition
Ray refers to one of the strap-shaped outer florets in the flower head of plants in the daisy family, such as sunflowers and zinnias. Each ray often looks like a single petal, but it is an individual flower, called a ray floret, attached to the central cluster of disc florets. Rays are usually sterile or female rather than fully bisexual, and they help give the flower head its radiating shape.
Function in Plants
- Pathway across wood: In woody stems, ray moves water, sugars, and stored nutrients sideways between the center and outer tissues. This radial transport complements the mainly up-and-down flow in xylem and phloem.
- Storage and recovery: Cells in ray often store starch and other reserves. During new growth, these reserves can be mobilized to support buds, leaves, flowers, or wound response.
- Clue in wood identification: The size, spacing, and visibility of ray are important features in wood anatomy. In some trees, prominent ray help distinguish species and can create characteristic figure on cut lumber.
- Link to healing and grafting: Because ray connects different tissues, it can take part in callus formation and the movement of resources around injured areas. Good alignment of living tissues matters in successful graft unions.
Related Terms
Xylem
Xylem is the plant vascular tissue that carries water and dissolved minerals from the roots to stems and leaves. It…
Phloem
Phloem is the plant vascular tissue that transports sugars and other organic nutrients made during photosynthesis from…
Vascular tissue
Vascular tissue is the plant transport system, made of xylem and phloem. Xylem carries water and dissolved minerals…
Stem
Stem refers to the main aboveground plant structure that supports leaves, buds, flowers, and fruits, and connects them…
Trunk
Trunk refers to the main woody stem of a tree, palm, or other tree-like plant. It forms the central upright axis…