medullary ray defined in 1951 yearmedullary ray - medullary ray;
medullary ray - Thin, vertical plate of parenchyma cells, one to several cells wide, running radially through tissues of stele. Medullary rays are either primary, passing from pith (medulla) to cortex between the primary vascular bundles, or secondary, formed from cambium during process of secondary thickening and ending blindly in secondary xylem and phloem. Since these latter have no connection with the pith (medulla) they are called by some authorities vascular (phloem or xylem) rays. Large numbers of medullary rays are present in the vascular cylinder and they form system of radiating plates of living tissue connected with each other by living parenchyma cells. The function of the medullary rays is in storage and radial conduction of synthesized food material.
near medullary ray in Knolik
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