How can you tell? (1 Viewer)

[Trebla]

When given a transverse or longitudinal diagram of a plant stem, how can you tell which is the xylem and which is the phloem? What features do you have to look out for? (In particular transverse diagrams like that in 2003 HSC Q13)

 

[Tim035]

Xylem vessels are usually larger and with thicker cell walls.
Phloem vessels are smaller and more numerous.

In a longitudinal section phloem will have visible companion cells and a sieve plate or sieve element. Xylem will have tracheids, pits and opened ends.