Tree Biology

Contents: - periderm - phellem - cork cambium - phelloderm - cortex - phloem- phloem rays - phloem - sieve tube element - companion cells - cambial zone (cambium) - bark - xylem - growth ring - vessels - tyloses - paranchyma - axial parenchyma - multiserrate ray paranchyma - uniserrate ray paranchyma - fibers - symplast - apoplast - growth ring/ray compartment - decay development

Click on any of the above terms to view its location in the tree cross section

Multiserrate rays are several cells thick in cross section and many cells 'deep' in longitudinal section. They extend into the xylem several to many growth increments. They transport sugars to and from the phloem and they are capable of storing tremendous amounts of starch. The rays are slightly swollen (thicker) in the vicinity of the growth increment boundary. This might function in physically holding the tree together.