There is no differentiation into cortex and stele in

Monocot stems lack clear differentiation between cortex and stele because their vascular bundles are scattered throughout the ground tissue. In dicots and monocot roots, there's a distinct separation between cortex (outside the vascular cylinder) and stele (central vascular tissue). Monocot stems have numerous vascular bundles embedded in undifferentiated ground tissue without an endodermal boundary separating cortex from stele.