medullary ray

noun Botany.

1. (in the stems of woody plants) one of the vertical bands or plates of unspecialized tissue that radiate between the pith and the bark.

noun

1. any of the sheets of conducting tissue that run radially through the vascular tissue of some higher plants

n.

1. The center of the renal, cortical lobule, consisting of the ascending or descending limbs of the nephronic loop or of the collecting tubules.Ferrein’s pyramid