Plant stems
The phloem is always on the outside and the xylem is always on the inside.
To remember which is on the inside and which is on the outside remember X-rays.
X-rays always see inside. The xylem which starts with an X for X-ray sits on the inside of the plant.
This can always be double checked because xylophones (xylem is pronounced zeye-lem) are usually made of wood. The wood is on the inside of the tree so the bark of a tree, which is on the outside must be the phloem.
The old dead phloem cells become the bark.
