Xylem is always in direct contact with phloem in the vascular bundles of

I. Dicot stem 

II. Gymnosperm stem  

III. Dicot leaf  

IV. Monocot stem
 

Xylem and phloem are in close contact in the vascular bundles of dicot leaf and monocot stem. They are described as closed vascular bundles. In the vascular bundles of dicot and gymnosperms stem, the xylem and phloem, though present in the same radius, possess cambium in between xylem and phloem and hence described as open vascular bundles.