Medullary ray

Medullary Ray

A Medullary Ray is a distinct anatomical feature found in woody plants and some herbaceous plants. It is a radial sheet or ribbon extending vertically through the tree across and perpendicular to the growth rings. Also known as pith ray or wood ray, these structures are significant in the transport of water and nutrients within the plant.

Structure and Function

Medullary rays are composed of parenchyma cells, which are living cells that differ from most other plant cells. They are thin-walled, and they have the ability to divide and differentiate into many types of cells, contributing to the growth and healing of the plant.

The primary function of medullary rays is to transport nutrients and water radially within the plant. This is particularly important in woody plants, where the distance from the central vascular system to the outer layers of the plant can be considerable. Medullary rays also serve as a storage system for nutrients, particularly starch, and can play a role in wound healing and the regeneration of the plant.

Significance in Wood Identification

In the field of dendrology, the study of wooded plants, medullary rays are an important feature for identifying wood species. The size, shape, and arrangement of the rays can be unique to certain species, and their presence can help distinguish between hardwood and softwood species.

See Also

• Vascular plant
• Wood anatomy
• Parenchyma